Likewise while you can look at historical Jews as a poor population with high IQ, you have the confounder that even then Jews placed a strong cultural value on education and intelligence. And therefore, even while they were poor, Jews were likely to work to improve themselves on both. Therefore this leaves open the question of how much of the difference is due to this cultural factor versus innate genetics.
In the case of Vietnamese boat people, we have families that literally risked their lives for a chance at a better future. This attitude taken to a new country suggests that we should expect them to make the most of any opportunity that they can find. How much of their subsequent success is due to this attitude?
On Nigerian immigrants, I'd need to see a source to believe your "generally better social outcomes" comment. https://en.wikipedia.org/wiki/Nigerian_Americans puts the 2018 median household income for members of the Nigerian diaspora into the USA at $68,658. https://www.census.gov/library/publications/2019/demo/p60-26... the median household income for white non-Hispanic households at $70,642. At least on the easiest to check social outcome, whites are still doing better.
That said, Nigerians who arrive here tend to be motivated and well-educated. I'm not sure how you can distinguish that from genetics. Doubly so since the poster child for racist claims about IQ is the poor performance of US blacks. Blacks whose African ancestry includes a significant share of Nigerian.
So yes, we can cite volumes of statistics. And it is easy for find lots of books like The Bell Curve that actually do. But when you dig in you won't find a single statistic whose difference can be clearly attributed to genetics rather than some cultural factor.
