Heat 1 Tablespoon of oil over medium heat. When hot, add chicken pieces and cook until chicken is no longer pink in the center.
Remove chicken from pan and discard cooking liquid.
Heat remaining oil over medium heat. When hot, add diced onion and bell pepper. Cook until slightly soft; then reduce heat to medium-low and add chopped garlic. Stir occasionally.
When onion is translucent, add chicken broth, chicken, Grille Sauce, black beans, chili powder, cayenne and peppers.
Simmer for 2-3 hours, uncovered.
For best results, after simmering, refrigerate overnight. When ready to reheat, simmer uncovered an additional 2 hours, stirring occasionally until sauce thickens and chicken breaks apart.