If nihilism was Nietzsche’s fear it was only because like Comte de Sponville, he feared its spread into the souls of millions. That said, Nietzsche’s philosophy cannot be understood apart from his monstrous jealousy of Jesus Christ together with his self-pity and longing for godlike powers. After his encounters with the disincarnate being that called itself Zarathustra, Nietzsche’s declaration of the death of the Christian God was an ecstatic utterance solidified in his description of himself as anti-Christ.
So, where's the philosophy and where's the insanity? And can you differentiate? At that I bow out as an unqualified amateur. That one needs a serious forensic shrink.