If a ceramic tile has a small chip. Do they have touch-up
Paint. Like they have for cars available??

Ceramic tile comes in so many different colors it would be nearly impossible for any store to stock all touch up paint. If you have a spare tile most paint store can put it into their paint computer and mix something up that is close. What color is your tile?

Since your tile is white you might find appliance touch up paint a good match. It's a bit harder than plain enamel.

A company called Ceramifix has tile touch up paint. Www.ceramifix.com