Fun fact coming from "pro" chess player. If we assume that Mao "wihout mindreading" is weaker at chess than Lelouche that game is not only winnable, but should be relativly easy. Every half-decent chessplayer assumes opponent can see all their plans anyway, so you will never play something you can see counter to. Therefore mind-read can only give Mao useless information, cuz the moment attack starts it is unstoppable...or at least one attacking can't see defence against it.
PS. Obviously in a game of equals that "cheat" would turn chances from 50/50 into something between 70/30-90/10 depending on skill lvl, but it still would be winnable, just harder