I would make a small wager that the woman driving this car, her ancestors don’t even come close to having been from Nubia. Somewhere throughout time, being “Nubian” had less to do about actually having ancestors who lived along this tiny region in the Sudan, than the fact that the Sudan happened to be in Africa, so it happened to apply to all of those who were of African descent, and then it turned into being a term to replace the word “black.”
The funny thing? It’s easy to accuse me of simply going to Wikipedia to find this information, but the thing is that I did a report of the Sudan back in grade school, and I actually did remember the region of Nubia. The capital of the country is also Khartoum, but that’s besides the point.