He is mistaken, powder coating will hold very well to the chrome so long as the place knows what they are doing. The chrome only needs to be scuffed up as though you were going to paint it, nothing more. I would suggest having it cleared though by them as well this will help with any scuffs and the like down the road also better UV protection. The only time you might have an issue is if they try to powder over already flaking chrome, if its not your good to go.
OH ya, i have powdercoated TONS of stuff right over chrome and i have never had a problem.
Here ya go, everything that was chrome etc has been powdercoated.
http://www.bonnevilleamerica.com/forums/...e=0&fpart=6