Nigerians have been studying and working in advanced English speaking countries since the early decades of the 20th Century. Long term or permanent migration was first to the U.K. In 2017 seven persons of Nigerian heritage were members of Parliament. More recently, migration to the U.S. grew at a faster rate than to combined U.K + Canada. Note that the graphic is of persons born in Nigeria, and does not include 2nd, 3rd generation Nigerians.
I have posted on Nigeria here, how they may be the highest educated immigrant group in the U.S.