The correct word for how to say the United States in Korean is 미국 (miguk). To say ‘an American’, as in an American person, add 사람 (saram) after the word 미국 (miguk). In other words 미국 (miguk)+ 사람 (saram) = 미국사람 (miguksaram). Alternatively, you may also say 미국인 (migukin) to illustrate the same meaning, though this form is usually used when speaking of another person as opposed to when referring to yourself.
https://www.90daykorean.com/united-states-in-korean/
Nips is racist because of Nippon , then there is Nigeria, slave trade capitol of the world, its all ridiculous we know what he meant and we know when its just a word
I think “-saram” is the Native Korean word for person and “-in” is the Sino-Korean word.