Do your silver, let it dry, and then hit it with some hair spray. Let it dry, do your top coat, let it dry.
Then where you want to do chipping, just wet the area with water and let it soak for a min. or so...take a sharpened tooth pick and chip away.
You can coat all over with the hairspray or just put it in the areas you want to chip, looks very convincing if done right, you even get a slight 3D effect as the chip is actually the absence of the paint, instead of painting a chip on over the top coat. Check out some of Jon Hayward's vids on chipping....makes it look easy.