I grew up in a very familiar boat as you OP. I'm the youngest in my family, so my parents had been living in the states for a decent while by the time I was born. When I went to school at first, it was majority white kids. I was usually the only black student, let alone Nigerian. When I moved I was around 14 years old and black people were more prevalent. It's strange because I never got teased for bring African or black at all beforehand, but when I started to associate with more black kids, I got the clicking noises, I got the African booty scratcher, anything you can think of.
I feel like black people specificslly target us Nigerians because.... we kind of do the same things. Nigerians are very prideful people and love to let it be known. Lots of Nigerians I know have said very rude things about blacks in general. This was more a thing for me when I was in middle and high school though, since I graduated people seem more interested on my Nigerian side and I get lots of love for it. So I kind of feel like a lot of it was just young ignorance.