If someone was born and raised in Poland, for example, then went to the United States and lived there, they would be considered Polish American.
My story, however, is a bit more complicated. I was born in Chile and stayed there with my family until I moved out as a child. Then, I lived in Brazil until I was 13 and moved to the United States. When I was 17, my family and I moved to France. Am I just Chilean-French or something? Chilean?
If asked, I would just say « Je suis né au Chili mais je réside à France maintenant. »
I would say you are a human and borders are arbitrary. and patriotism, and dividing people up by their country is a silly ancient practice that needs to be removed from society, so we stop fighting over land and immigration.
But if it matters to you, then just consider yourself American. Your current nationality. You can always say you were born in Chile, but now you are American.