Is this racist?

As some people know in my school or just assume I'm half Asian, specifically Korean don't worry not north, but it's weird because some people may know this without me knowing them, I mean when I was younger I used to introduce myself as hi this is my name and I'm Korean, which I know can be a bit awkward, but what's weird and uncomfortable is that one of the guys I've known for a while has all the sudden started calling me Ching Chang, because of my Asian heritage, and I've made it clear that I'm uncomfortable with being called that and I don't like it, my real question is... Is it racist and what should I do to stop it?

Is this racist?
Post Opinion