im pretty sure chuck has no intention of ever using that tape to ruin jimmy. i think he did it just to see if he could stoop to jimmy's level and outcon his own brother. and he could, which is probably terrifying to chuck who is a by the numbers at all costs kinda guy. the second jimmy finds out what chuck did, that will be a huge affirmation that chuck also will get down in the mud with him and jimmy wins. it also is flimsy at best because there is no proof other than that tape and jimmy even says "you arent just saying this to make me feel better are you? "and jimmy responds with "of course i am". all jimmy has to say is, my brother is fucking nuts and i would say anything to keep him under control. bam end of story. the only people who would believe that confession is maybe howard and kim. since kim already knows, all hes got is howard who really doesnt give too many fucks about jimmy.