In a large skillet over medium-high heat, heat oil. Add bell pepper and green onions and cook until tender, 5 minutes. Add garlic and cook until fragrant, 1 minute. Add chili powder and cumin and stir until combined, then season with salt.
Add ground beef and cook until no longer pink, 5 minutes more.
Add diced tomatoes and black beans and stir until combined. Stir in hot sauce, Monterey jack, and cheddar. Cover with a lid and let melt, 2 minutes, then garnish with green onions and serve.
