"My demand of the philosopher is well known: that he take his stand beyond good and evil and treat the illusion of moral judgment as beneath him. This demand follows from an insight that I was the first to articulate: that there are no moral facts. Moral and religious judgments are based on realities that do not exist. Morality is merely an interpretation of certain phenomena — more precisely, a misinterpretation."
As I see it, what I call nihilism is primarily just the honest acknowledgment that one does not know "right from wrong," in any deep, metaphysical sense. One may know one's own emotional reaction to a given phenomenon (you may react with disgust and disapproval at the notion of, say, willful murder or some particular instance of cruelty) but this says more about your own constitution than it does about the phenomenon in question. We shouldn't mistake our own emotional reactions to phenomena as indicators of moral truth, though this is not to say that we should treat these reactions as irrelevant, or just ignore them. When we react with great disgust and disapprobation upon witnessing or hearing about some event, we "misinterpret" the phenomena in question by assuming that these sentiments highlight some objective "moral fact."
While an objective morality may be out the window, I don't think this means that we ought to abandon ethics, so long as we consider "ethics" to mean something like "dealing with the question of how to live best." The question of how to live and act is perpetually relevant, and this is so even in the absence of genuine free will or final, static answers to such a question.