In a large skillet over medium heat, cook the ground beef until browned and fully cooked, breaking it up as it cooks. Drain any excess grease.
Add the diced green peppers, onions, ketchup, yellow mustard, Worcestershire sauce, tomato paste, chili powder, and salt directly to the crockpot. Stir to combine.
Add the cooked ground beef to the crockpot and mix well.
Cover and cook on LOW for 6–7 hours or HIGH for 3–4 hours, stirring once or twice if possible.
Taste and adjust seasoning if needed, then serve warm.