The subject of the article is the analysis and assessment of the changes introduced in 2023-2024 in the legal framework of the so-called basic decision, regulated by the provisions of Chapter 1a of the Act of June 29, 2011 on the preparation and implementation of investments in nuclear power facilities and related investments. To date, a total of ten decisions-in-principle have been issued in favor of five different entities intending to implement both large and small nuclear reactors. Amendments to the Special Nuclear Power Act, which came into force in 2023-2024, introduced a number of changes to the structure of the decision-in-principle, including, inter alia, its subject and position in the licensing procedure for nuclear energy facilities, elements of the application for initiation of administrative proceedings, as well as the conditions for its issuance and components of this decision. At the same time, issues related to changes in the ownership structure of the investor who obtained the decision-in-principle, or the company that is a partner or shareholder in this entity, were regulated. In addition, the competence of the authority conducting the proceedings has been changed and the circle of cooperating (opinion-giving) authorities in the matter of issuing the decision-in-principle has been expanded. The aim of the article is to assess the changes introduced, to point out doubts of interpretation and to propose de lege ferenda postulates for changes in the regulations in the analyzed area.