Nihilism does exist, but as a temporary state. I can personally attest to having periodic bouts with nihilism, but nobody lives in that state permanently. And some also believe that nihilism can exist on the cultural scale as well as the individual. (Nietzsche, for instance, believed that civilization under Christianity was approaching a nihilistic crisis because it no longer believed in itself.) But yes, as a declared belief, I think you're right. The act of declaring it essentially negates the concept.
As for progress, as I think I've argued before, the word implies movement toward happiness. Happiness is, by definition, the ultimate telos or we have no reason to exist at all. If, however, we are condemned to the same patterns of violence, subjugation, and suffering, then one has to ask how progress is truly possible, despite the alteration of our external, empirical reality through technology. It's a question that's highly deceptive in its apparent simplicity, but one that people devote their entire careers attempting to answer.
