Opponent was the unfortunate person who was playing a game of chess against Nate at the beginning of the Season 3 episode The Jerk. He was portrayed by actor Ben Bledsoe.
Nate was the better player and was constantly belittling him during the game. After Nate won, he put out his hand to congratulate Nate and say "good game", but instead Nate fixed his stare on him and started beating him severely.