I cannot find any info about Sims 4 being a "region locked" game. However, just because there is no specific information about that topic, that does not guarantee you will be able to play the Sims 4 purchased in the US on your laptop / desktop in Nigeria.
Having said that if the Sims 4 was actually a region locked game, I would expect to have found complaints about it. But I have not. Therefore, I believe you should be able to play the "US version" of Sims 4 in Nigeria.