A better question is does Nick Szabo even exist, rather than is he who he claims to be. We have no photos of him, and the University he claims to work at denies he was ever employed there.
Is he a real person, or just another pseudonym like Satoshi Nakamoto? If he really is/was a professor, then surely students who went there would have had interactions with him and can verify that he exists.
What proof is there that Nick Szabo is a real person?