[frenchtoast8]

He's accused Luis Paulo Supi (Brazillian grandmaster) a few times after losing to him, and he accused Andrew Tang after losing to him. The latter was criticized in some online circles because it was seen as bullying a then 14 year old.

I don't know many other notable cases of Nakamura accusing players of cheating. Many players dislike how Nakamura conducts himself on stream and how he interacts with the chess community and this leads to exaggeration. It's simply wrong to compare him to Kramnik, who has dedicated many hours over the last couple years to accusing players.