Loughner didn't see himself as a nihilist. He saw himself as fighting nihilism. This is evident in his fixation in his YouTube videos on the idea that words have no meaning, or have somehow lost their meaning in a process of nihilistic decline—a fixation that seems to lie at the basis of his tragic grudge against Gabrielle Giffords.
Nietzsche, oddly, has suffered a similar fate. Because of his assault on religion and rationalist metaphysics, and because of the hints of anarchy in his assorted visions of the future (e.g., "the transvaluation of all values"), he's taken as the West's über-nihilist. But he saw himself as the scourge of European nihilism, and possibly also its remedy. Nietzsche saw nihilism as a disease, which grows from, in Alexander Nehamas' words, "the assumption that if some single standard is not good for everyone and all time, then no standard is good for anyone at any time." It presents itself as mindless hedonism and flaccid spirit, but also as fanaticism.