in my opinion, it will always be nobody. this was back before the meta was defined, nobody understood the game like nobody else at the time, nobody could touch him. he was pretty much a god in every mod he played, and additionally is one of the best/most influential replay makers ever with his creative hacking and tricking replays.
now, nobody at his prime is probably outclassed by modern duelers simply because of how the meta progressed, but for his time nuthug was a menace. so yeah, in my mind, nobody is the GOAT