Researchers have raised concerns about teachers' ability to embed nature of science (NOS) in their science instruction, a complicated situation that is certainly impacted by the availability of adequate resources to assist K-12 science teachers. In light of the implementation of the ideas from the "Framework for K-12 Science Education" and the "Next Generation Science Standards" in the USA, this study sought to identify and evaluate resources aimed at guiding NOS instruction. A search of the National Science Teachers Association (NSTA) database for Next Generation Science Standards (NGSS)-aligned instructional resources resulted in an analytical sample of eight lessons. All materials accompanying these lessons were analyzed for their representations of 10 NOS aspects. The evaluation of these materials revealed a prevalence of implicit, naïve representations in the sample lessons (60.4% of all NOS aspects addressed). Examination of the connections to NOS in these lessons leads to a set of recommendations to improve the quantity and quality of NOS representations in future NGSS-aligned instructional resources. The analytical approach used and the issues raised about the presentation and treatment of NOS in precollege lessons are of interest to the broader science education community.