Haven't found any online betting involve in chess games on the internet. I've been playing for almost 10 years since I was a kid and Chess.com is far the best online Chess website for me. But I don't know if there was a platform which offers a bet on games and uses crypto as its money. Kindly update the thread OP if ever you found a legitimate one.

But I don't think it is possible as most games are done in numerous hours unless it is blitz or a casual match, and it is too complex to bet on a player because blunders often happen and it is not a team fight.