everybody says this, but i don't really buy it.
in my experience, there are people that have this word in ~regular usage, and there's everybody else. if this was a word he threw around, we'd have heard him say it by now, either on recording/video pre-presidency, or when he goes off-script at his rallies/briefings. in fact, i don't even think he's a racist, in the conventional sense of the word. i've seen zero evidence that he treats poor white people better than poor black (or brown) people. he treats everybody like shit, because he thinks everybody is beneath him, regardless of the color of their skin. he's shitty to anyone who's not in a position to help him or give him things.
i believe that he uses racist/nationalist/supremacist language intentionally to rile up the racists that vote for him, because he's transactional and he only cares about getting elected. he'd address the nation in black-face if he thought it would help him win.