In a large bowl, combine beef with beans, tomatoes, 1 cup cheese, rice, corn, cumin, chili powder, garlic powder and oregano. Stir until all ingredients are fully incorporated. Season with salt and pepper.
Stuff peppers with beef mixture and place them in Crock-Pot, open side up. Cover and cook on high for 3 hours.
When peppers are tender, top peppers with remaining cheese and cover. Cook on low for 5-10 minutes more, or until cheese melts.
Garnish with cilantro and sour cream and serve.
