NexGen Energy - 40-F annual report 2021

. See Exhibits 99.4, 99.5, 99.6 and 99.7 to this Annual Report on Form

. As of the end of NexGen’s fiscal year ended December 31, 2021, an evaluation of the effectiveness of NexGen’s “disclosure controls and procedures” (as such term is defined in Rules and of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) was carried out by NexGen’s management, with the participation of its principal executive officer and principal financial officer. Based upon that evaluation, NexGen’s principal executive officer and principal financial officer have concluded that as of the end of that fiscal year, NexGen’s disclosure controls and procedures are effective to ensure that information required to be disclosed by NexGen in reports that it files or submits under the Exchange Act is (i) recorded, processed, summarized and reported within the time periods specified in Securities and Exchange Commission (the “Commission”) rules and forms and (ii) accumulated and communicated to NexGen’s management, including its principal executive officer and principal financial officers, to allow timely decisions regarding required disclosure.

. For management’s report on internal control over financial reporting, see “Disclosure Controls and Internal Control Over Financial Reporting – Management’s Report on Internal Control Over Financial Reporting” in our MD&A attached as Exhibit 99.2 to this Annual Report on Form and incorporated by reference herein.

. The required disclosure is included in the Report of Independent Registered Public Accounting Firm on NexGen’s internal control over financial reporting that accompanies NexGen’s Audited Consolidated Financial Statements for the fiscal years ended December 31, 2021 and 2020, filed as Exhibit 99.3 to this Annual Report on Form

. During the fiscal year ended December 31, 2021, no changes were made in NexGen’s internal control over financial reporting that have materially affected or are reasonably likely to materially affect NexGen’s internal control over financial reporting.

NexGen’s audit committee all audit and services provided to NexGen by its external auditor, KPMG LLP. Also see “Audit Committee Disclosure – Policies and Procedures” in NexGen’s Annual Information Form for the fiscal year ended December 31, 2021, filed as Exhibit 99.1 to this Annual Report on Form

Of the fees reported in Exhibit 99.1 to this Annual Report on Form under the heading “Audit Committee Disclosure – External Auditor Service Fees (By Category”, none of the fees billed by KPMG LLP were approved by NexGen’s audit committee pursuant to the exception provided by Section (c)(7)(i)(C) of Rule of Regulation