Crumble ground beef into a soup pot over medium-high heat. Cook and stir until evenly browned, 7 to 10 minutes. Drain off all but 1 to 2 tablespoons grease.

Add onion, 1 1/2 teaspoons cumin, and red pepper flakes; cook and stir until onion is tender, about 5 minutes. Pour in chicken broth, condensed soup, and tomatoes; season with chili powder, salt, and pepper. Simmer for 30 minutes.

Pour in pinto beans, season with remaining 1 1/2 teaspoons cumin and cayenne pepper, and simmer for 30 more minutes.