In a large skillet, saute onion in 2 Tablespoons butter over medium heat for about 3 minutes. Add the peppers and cook 2 more minutes. Stir in the garlic.
Stir in the uncooked rice, bouillon, water, sour cream, chicken, green chilies, salt, pepper, cumin, and chili powder. Bring to a boil, then reduce heat to low.
Cover and simmer for 15-20 minutes or till rice is tender, stirring once or twice.
Sprinkle cheese over the top. Replace the lid and cook till cheese melts.