Be thankful your countertop is Corian; it can be repaired.
In most cases, a color-matched piece of material is used. If you don’t have an extra piece of the Corian in your home, you can use a piece from the the backsplash that runs up the wall from the countertop. That piece of the backsplash can then be repaired less noticeably.
However, this is not a do-it-yourself project. It would cost you more to get all the equipment to make the repair than it would to hire a specialist to fit it. Plus it takes a well-trained hand to make the chip look like it was never there. Give one of our countertop specialists a call. You can find them listed on our countertop page.