Calling Nietzsche a nihilist is a complete misrepresentation of him. He wrote on nihilism a lot, but only to criticize it. Nietzsche believed holding a nihilist viewpoint to mean that one, in short, has failed at life.

It's more accurate to call Nietzsche an existentialist, as long as one keeps in mind that this term can refer to a wide spectrum of different moral and ontological ideas.