Since the Peruvian natives chew on coca leaves to reduce the effects of altitude sickness, this racial slur was coined to refer to any Peruvians.
Jim: I've been wanting to go to Machu Picchu, do you know any coca chewers?
Trina: I heard that Art is Peruvian. I mean, look at his nose, it's obvious.
Jim: Yeah, those coca chewers need a larger schnoz to be able to breathe high up in those Andes mountains.