Expert witnesses may proffer testimony that embraces ultimate issues (such as a defendant’s mental state when he or she has entered a not-guilty-by-reason-of-insanity plea). However, such testimony must be otherwise admissible and not stray from opinions about factual matters to conclusions about the appropriate verdict.
Nelson, Joshua, "Pundyk v. State, 136 Nev. Adv. Op. 43 (July 16, 2020)" (2020). Nevada Supreme Court Summaries. 1334.