If the chrome plating is high quality, you can powdercoat a clear over the top of it...it will reduce the shine slightly, but it will keep it from tarnishing. It works on polished aluminum too.
Eastwood also sells a product in a can called "Diamond Clear" that is a spray on clear coat for polished metal.
Lastly, there is a product called Zoopseal that protects for up to a year...kind of expensive though.