Agreed, if you mean African American culture ( versus non-USA Black culture ).
I'm sure that the Nigerians that I know would say they are part of, and have been raised in a Black culture ( as it applies to them ), but I've yet to hear one of them say he is an African American.
AAMOF, as I've said, Nigerians in the US are very successful as to education levels, income, and family cohesiveness.
I don't have time to check it, but I'm pretty sure that most sizable homogenous Black immigrant groups like Jamaicans are relatively successful in the US, and certainly more so than African Americans.
But groups like Ethiopians, and Somalians which are much smaller, struggle a lot and are not as successful as Nigerians, and probably African Americans. This could have to do with the legal immigrant experience versus a forced refugee experience.
I guess this points out that the "Black outcome" in the US is more than just a function of skin color. What advantages do Nigerians have over African Americans that leads to better outcomes? What disadvantages do African Americans have that Nigerians do not that leads to lesser outcomes? I'm sure there has been much study about this, and I'll look it up later.