NMG 6-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TORULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of December 2025

Commission File Number: 001-40416

Nouveau MondeGraphite Inc.****(Translation of registrant’s name into English)

481 rue BrassardSaint-Michel-des-Saints, QuebecCanada J0K 3B0

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F   ¨          Form 40-F   x

DOCUMENTS TO BE FILED AS PART OF THISFORM 6-K

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, there unto duly authorized.

Exhibit 99.1

PRESS RELEASE

For immediate release

NMG AnnouncesOvernight Marketed Public Offering

MONTRÉAL,CANADA, December 17, 2025 – Nouveau Monde Graphite Inc. (“NMG” or the “Company”) (NYSE: NMG, TSX: NOU) intends to commence an overnight marketed public offering of common shares of the Company (“Common Shares”) (the “Offering”).

Maxim Group LLC is acting as sole placement agent for the Offering.

The number and pricing of Common Shares offered pursuant to the Offering will be determined in the course of marketing and in the context of market conditions and other factors, with the final terms of the Offering to be determined at the time the Company enters into a definitive placement agency agreement with the placement agent (the “Placement Agency Agreement”).

The Company intends to use the net proceeds from the Offering for procurement of long-lead equipment to initiate certain construction activities, and to cover detailed engineering and indirect costs for the Matawinie Mine project, to fund engineering activities to deliver an AACE class 3 estimate for the 13ktpy Bécancour Battery Material Plant project, and to fund general working capital and corporate expenditures.

The Common Shares to be offered under the Offering will be offered solely in the United States pursuant to a supplement to the Company’s registration statement on Form F-10 registering the Common Shares under the United States Securities Act of 1933, as amended, (the “U.S. Securities Act”) pursuant to the Multi-Jurisdictional Disclosure System adopted by the United States and Canada (the “MJDS”). No Common Shares will be offered or sold in Canada.

In connection with the Offering, the Company will file a preliminary prospectus supplement and will file a final prospectus supplement (together, the “Prospectus Supplement”) to the Company’s existing short form base shelf prospectus dated December 5, 2025 filed in Canada (the “Base Shelf Prospectus”) and the Company’s United States registration statement on Form F-10 (the “Registration Statement”) filed with the U.S. Securities and Exchange Commission (the “SEC”) under the U.S. Securities Act, pursuant to the MJDS. The Prospectus Supplement, the Base Shelf Prospectus and the Registration Statement contain important information about the Company and the Offering. Prospective investors should read the Prospectus Supplement, the Base Shelf Prospectus, the Registration Statement and the documents incorporated by reference therein before making an investment decision. The Prospectus Supplement when filed in Canada (together with the related Base Shelf Prospectus) will be available on SEDAR+ at www.sedarplus.ca. The Prospectus Supplement when filed in the United States (together with the Registration Statement) will be available on the SEC’s website at www.sec.gov. Copies of the preliminary prospectus supplement and accompanying prospectus may be obtained by contacting Maxim Group LLC, at 300 Park Avenue, 16th Floor, New York, NY 10022, Attention: Syndicate Department, or by telephone at (212) 895-3745 or by email at [email protected]. The Prospectus Supplement contains important, detailed information about the Company and the proposed Offering. Prospective investors should read the Prospectus Supplement (when filed) before making an investment decision.

Closing of the Offering will be subject to a number of customary closing conditions, including NMG receiving all necessary regulatory approvals and the approval of the Toronto Stock Exchange and the New York Stock Exchange. There can be no assurance as to whether or when the Offering will be completed, or as to size or terms of the Offering.

This press release does not constitute an offer to sell or the solicitation of an offer to buy securities, nor will there be any sale of the securities in any province, state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such province, state or jurisdiction. The securities being offered and the contents of this press release have not been approved or disapproved by any regulatory authority, nor has any such authority passed upon the accuracy or adequacy of the Prospectus Supplement, the Base Shelf Prospectus or the Registration Statement.

About NouveauMonde Graphite

Nouveau Monde Graphite is an integrated company developing responsible mining and advanced processing operations to supply the global economy with carbon-neutral advanced graphite materials. The Company is developing in Québec, Canada, a fully integrated ore-to-processed-graphite value chain to serve tomorrow’s industries in energy, defense, technology, and manufacturing. With recognized ESG standards and structuring partnerships with major customers, NMG is set to become a strategic supplier of advanced materials to leading specialized manufacturers while promoting sustainability, innovation, and supply chain traceability. www.NMG.com

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CautionaryNote Regarding Forward-Looking Information

This pressrelease contains “forward-looking information” and “forward-looking statements” within the meaning ofapplicable securities legislation (collectively, “forward-looking statements”), including, but not limited to,statements relating to future events or future financial or operating performance of the Company and reflect management’sexpectations and assumptions regarding the Company’s growth, results, performance and business prospects and opportunities.Such forward-looking statements reflect management’s current beliefs and are based on information currently available to it.These forward looking statements include, but are not limited to, the information concerning the Offering, including thejurisdictions in which the Common Shares will be offered, the anticipated offering size, the entering into of the Placement AgencyAgreement, the completion of the Offering, the anticipated use of the net proceeds from the Offering, the receipt of all necessaryapprovals, and the expected results of the initiatives described in this press release, and those statements which are discussedunder the “About Nouveau Monde” paragraph and elsewhere in the press release which essentially describe theCompany’s outlook and objectives.

Forward-lookingstatements are based upon a number of estimates and assumptions that, while considered reasonable by the Company as of the time of suchstatements, are inherently subject to significant business, economic and competitive uncertainties and other factors that may cause theactual results, level of activity, performance, or achievements of the Company to be materially different from those expressed or impliedby such forward looking statements.

Forward-lookingstatements are subject to known or unknown risks and uncertainties that may cause actual results to differ materially from those anticipatedor implied in the forward-looking statements. Risk factors that could cause actual results or events to differ materially from currentexpectations include, among others, availability financing or financing on favorable terms for the Company, delays in finalizing thedefinitive agreements, delays in reaching FID, and general economic conditions, as well as earnings, capital expenditure, cash flow andcapital structure risks and general business risks. A further description of risks and uncertainties can be found in NMG’s BaseShelf Prospectus dated December 5, 2025, and NMG’s Annual Information Form dated March 31, 2025, in the sectionentitled “Risk Factors”. These documents are available on SEDAR+ at www.sedarplus.ca and on EDGAR at www.sec.gov. Unpredictableor unknown factors not discussed in this Cautionary Note could also have material adverse effects on forward-looking statements.

Many of theseuncertainties and contingencies can directly or indirectly affect, and could cause, actual results to differ materially from those expressedor implied in any forward-looking statements. There can be no assurance that forward-looking statements will prove to be accurate, asactual results and future events could differ materially from those anticipated in such statements. Forward-looking statements are providedfor the purpose of providing information about management’s expectations and plans relating to the future. The Company disclaimsany intention or obligation to update or revise any forward-looking statements or to explain any material difference between subsequentactual events and such forward-looking statements, except to the extent required by applicable law.

Further informationregarding the Company is available in the SEDAR+ database (www.sedarplus.ca), and for United States readers on EDGAR (www.sec.gov),and on the Company’s website at: www.NMG.com.