>But in the last two episodes we've seen Chuck "challenge"
>Jimmy twice and twice we've seen him come away either
>impressed (when Kim reassured Jimmy) or rebuffed.

I absolutely did not come away from either episode thinking Chuck had anything other than disdain and doubt in his mind regarding Jimmy's answers. His facial expressions, to me, said "he's lying to us"

Just the way I read his looks, of course. I could be wrong as well.