In a large skillet heat 2 tablespoons of the oil over medium heat. Saute the garlic, bell pepper, onion, celery and mushrooms for 5 minutes. Set aside.
Add the remaining 1 tablespoon of oil to the skillet and brown the chicken over high heat until it is golden brown and firm on the outside. Return the vegetable mixture to the skillet.
Add the chili powder, cumin, oregano, paprika, cocoa powder, salt, hot pepper flakes and ground black pepper to the skillet. Stir for a few minutes to prevent burning. Add the tomatoes and beans, bring all to a boil and reduce heat to low. Cover the skillet and simmer for 15 minutes, then remove cover and simmer for 15 more minutes.
