Exhibit 99.1 Condensed Interim Consolidated Financial Statements For the three months ended March 31, 2023 (expressed in thousands of Canadian dollars) - Unaudited NexGen Energy Ltd. Condensed Interim Consolidated Statements of Financial Position (expressed in thousands of Canadian Dollars) - Unaudited As at March 31, 2023 As at December 31, 2022 Assets Current assets Cash $ 135,909 $ 134,447 Marketable securities (Note 5) 5,385 5,775 Amounts receivable 1,917 1,801 Prepaid expenses and other assets 2,771 2, ...