Most wheel refinishing companies can make minor repairs or touch up minor chips. If you are in Southern California I can recommend someone who can fix anything from a minor chip to major curb rash. Just ask TubeGuy! Ask your local wheel guy or dealer who they use to fix curb rash on wheels. That person will have access to whatever you need.
I know I can go to a wheel refinishing place which I would do if I wanted to totally refinish the wheel, but I'm talking about just touching up tiny little nicks and chips.