Heat a large pot over medium-high heat. Cook and stir beef in the pot until browned and crumbly, 5 to 7 minutes; drain and discard grease.
Stir cheese, kidney beans, tomato sauce, tomatoes, green chilies, red onion, and cayenne pepper with the beef. Reduce heat to low. Cook and stir beef mixture until the cheese is melted completely, about 10 minutes.