You know, they made it that Scar just took Kovu in, and that Kovu's not his real son so the relationship between Kovu and Kiara wouldn't be weird, because they would be relatives in some way.
But the thing is, Nuka and Vitani are Scar's actual children, and since Scar is Simba's uncle, that would make Nuka and Vitani his cousins, right?"
I never payed attention to this before, it just struck me now, and it's really wierd, too!
Who would have thought?