+1 to what's already been said. Fortunately it's on the painted part rather than the diamond cut part. Once you've filled in the chip with paint, it'll be worthwhile using a hard wax or a sealant to protect the wheels from the elements too. At the cheaper end of the scale, the Autoglym Alloy Wheel Protector will do the job, and at the other end there are ceramic sealants such as Gtechniq C5 and CarPro DLUX.