Sand your chrome surface with a fine-grit sandpaper, using a power sander. Move the sander in a crosshatch fashion to make sure the grain isn't all in one direction. Dust off the excess powder and clean the area with thinner.
Spray the chrome with spray etching; a few light coats will do. Let this etching sit for a few minutes, then spray the chrome with a urethane primer, about the same number of coats. Allow this to set for a few hours.
Use the sander on the chrome, this time with a medium-grit sandpaper. Use the same crosshatching technique as before, however, don't use thinner to clean off the chrome. Dust thoroughly, then use a spray sealer to bind to the scratches ground into the chrome. Use a few layers of auto spray paint on the chrome to finish the job.