Needless to say, this is a nickname for a very specific kind of dude, not specifically one who plays chess.
This is the kind of guy who always makes all the right plays, and receives an ungodly amount of rizz.
The "right plays" is originally based off the terminology used in the game, Chess.
Person 1: Hey! Did you see that sick guy at the party?
Person 2: How could I miss him?! He was a total Chessman!
This is the pinnacle of humour, the true most succulent joke in the entire world. it is impossible to read and not crack a smile. this saying, the anger of god dimp.
Person 1: "Why is dimp?"
Person 2: "A child"