Introduce them to chess boxing
Chess and Wrestling

The strategic and tactical lessons of chess which are applicable to wrestling (and most other contests) are so general, that they can be learned from almost anywhere: attack weak points, concentrate power in attack, speed and mobility are really good, use small attacks to set up advantageous conditions, accurately evaluate the strengths and weaknesses of your position and your opponent's.
In any event, perhaps instead of trying to convince wreslers of the utility of chess, demonstrate to them that chess is a just as fierce, brutal, and personal as wrestling is. It's just mental instead of physical.
I am attempting to convince the jr/hs wrestlers that it is beneficial to be part of the chess club and learn the aspects of chess because the strategies of chess can help a wrestlers mindset. But unfortunately, I cannot find anything that corroborates my belief. Anyone know where I can find that kind of information?