2002 Chevy Monte Carlo Timing chain replacement

My Monte needs to have a valve job because the exhaust valve in cylinder 6 is not seating properly. I was told that the timing chain does not need to be replaced. Is this the case? I do not want to have to put out the money for the valve job only to have the timing chain go and have to do this all over again. I have already rebuuilt the tranny and varous other things on this car and intend to have it for a long time. Please advise if I should replace the timing chain as well.
Thank you