No, not a fat woman. Nubian queen is what many Black men used to call Black women in the 70s and stuff, I have no idea why you put weight into it.

I think they just think it is funny that he is wearing that shirt. Simpsons is not funny like it used to be, that is for sure

I think it's because the t-shirt is pink and it says princess, and police officers don't do that... That's possibly what the picture is about?

Black it fine.

During this episode of the simpsons when bart is selling t shirts

Chief Wiggum takes this one ( Proud Nubian Princess ) when the police bust Bart's stand and confiscate the shirts; it's the only one that fits him.)

Im guessing the joke is a Nubian Princess is a large black woman ? But I'm not sure and i'm afraid to ask becues I don't want to offend anyone.