When you read the thoughts of Friedrich Nietzsche, you can tell almost immediately that he is a pure nihilist who had many brilliant ideas. He just didn't think there was much of a point to anything. The man is sort of an enigma, and some of his ideas conflict, but whether he is a nihilist isn't up for debate. He simply was.
I personally think that Friedrich Nietzsche should be considered as a nihilist because he is known for associating with Germane philosophers. The reason Friedrich Nietzsche should have been considered as a nihilist is because he had so many different things as well as different subjects to consider. Friedrich Nietzsche should have been considered because of the background in which he comes from.
Friedrich Nietzsche practically wrote the book on modern nihilist philosophy, so of course he should be considered a nihilist. Even though Nietzsche didn't exactly write glowing reviews of nihilism, he at least concluded that he was part of that culture since he faced many of the same problems that nihilists wrote about.
Obviously if you define nihilism as wikipedia does, "a philosophical octrine that suggests the lack of belief in one or more REPUTEDLY MEANINGFUL ASPECTS of life," then yeah no shit, Nietzsche is a nihilist and SO IS ANYONE WITH A CONTROVERSIAL THEORY OF MEANING.
But if we go by the Internet Encyclopedia of Philosophy's definition, "the belief that all values are baseless and that nothing can be known or communicated" it's rather hard for anyone to actually BE a nihilist. Because continuing to live and breathe rather than killing yourself is an affirmation of values.
Stating Nietzsche was a Nihilist is kind of like saying Marx was a socialist. The statement is true for some views and false through other perspectives. Labeling him as a nihilist is such a stringent definition that I could not agree. I would say Nietzsche had a healthy respect for nihilism, but did not indulge in it fully, and thus he could not be defined as a nihilist.
No, this man should not be considered someone who does not believe in any religion. Whether or not he actively practiced any religion was a personal choice by him, but he was a very smart man, and had many great works and poems. He was never acting as an nihilist.