LOL. You might want to look at that image a little closer. Yes some of the Nubians have pitch black skin, but look at the others. They have reddish brown skin like the Pharoah and his horse.
I know white people see us black folk as being all the same but we do actually come in different shades. Some Africans can be a lot darker than others. In particular those from Sudan (which is where Nubia was located). The Nilotic peoples of Sudan are famous for being among the darkest in the world. So it makes perfect sense when your closest neighbors are darker than even other Africans that most Nubians would be represented as being a darker hue.
With that said, the image you posted still contradicts your point because a closer inspection would have told you thar half of the Nubians Ramses is trampling with his horse have the same skin color as him.
Trying to have a respectful conversation and you’re being disingenuous