In a large pot melt the butter over medium heat. Add the chicken, onion, bell pepper and garlic. Cook mixture for 8-10 minutes, or until chicken is done.
Add the broth, enchilada sauces, corn, pinto beans, black beans, diced tomatoes, cumin, and chili powder. Bring to a boil, then turn down the heat and simmer for 30 minutes.
Add the cheese and sour cream and stir until melted. Garnish with green onions and tortilla chips.