Providing you have the onward MAN ORD/LAS tix at BKK they could thru-ck you. If, as I suspect, you might p/up the MANORD/LAS tix at MAN they won't check you baggage through and you will have to reclaim in T1. Even then 2hrs 20min should be ok . Don't forget the massive security queues ex T3 ! Good luck!
