Anyone can sue anyone else over anything: the question is, what's their chance of success?
In this case, zero to nothing: Chess.com is happy to review any instance of account closure, but if after the review the account remains closed, they're fine with taking that decision to court if they have to - that's the level of confidence they have to have when they close an account for Fair Play violations.
Can players sue chess.com if there account is closed for cheating if the subject player wasn't cheating ?