" One important reason that philosophers should take Nietzsche seriously is because he seems to have gotten, at least in broad contours, many points about human moral psychology right. Consider:

(1) Nietzsche holds that heritable type-facts are central determinants of personality and morally significant behaviors, a claim well supported by extensive empirical findings in behavioral genetics.
(2) Nietzsche claims that consciousness is a “surface” and that “the greatest part of conscious thought must still be attributed to [non-conscious] instinctive activity,” theses overwhelmingly vindicated by recent work by psychologists on the role of the unconscious (e.g., Wilson 2002) and by philosophers who have produced synthetic meta-analyses of work on consciousness in psychology and neuroscience (e.g., Rosenthal 2008).
(3) Nietzsche claims that moral judgments are post-hoc rationalizations of feelings that have an antecedent source, and thus are not the outcome of rational reflection or discursiveness, a conclusion in sync with the findings of the ascendent “social intuitionism” in the empirical moral psychology of Jonathan Haidt (2001) and others.
(4) Nietzsche argues that free will is an “illusion,” that our conscious experience of willing is itself the causal product of non-conscious forces, a view recently defended by the psychologist Daniel Wegner (2002), who, in turn, synthesiyes a large body of empirical literature, including the famous neurophysical data about “willing” collected by Benjamin Libet. "

― Brian Leiter , Nietzsche and Morality