I don't think it is. The people that are native to America are, wait for it, Native Americans. However a name exists that is controversial, Indian. The Europeans that settled here chanced upon the Native Americans early in their stay. In the beginning they thought they were in India hence incorrectly referring to the natives as such. The name kinda stuck despite them not being in India. I guess the term NA could be considered a controversy to those that treat north and south america, collectively as America and there aren't any NA in south america.