In a large pot, heat a tablespoon of oil over medium heat.
Add the diced onion and bell pepper, sautéing until soft.
Stir in the minced garlic, cooking for an additional minute.
Season the vegetables with cumin, chili powder, salt, and pepper.
Add the chicken breasts and brown them on both sides.
Pour in the diced tomatoes and chicken broth.
Bring the mixture to a simmer and cover the pot.
Cook for about 20 minutes, or until the chicken is cooked through.
Remove the chicken, shred it, and return it to the pot.
Stir in the cooked white beans and heat through before serving.