Combine bell peppers, onion, garlic, tomato sauce, diced tomatoes, broth, chili powder, paprika, ½ teaspoon salt, pepper, cumin and saffron (or turmeric) in a 6-qt. slow cooker.
Nestle chicken into the mixture until submerged.
Cover and cook on Low for 5 ½ hours.
Stir in rice, peas and the remaining ½ teaspoon salt.
Cover and cook until the rice is tender and most of the liquid is absorbed, about 30 minutes more.
Using 2 forks, shred the chicken in the slow cooker.
Top each serving with 1 tablespoon olives and garnish with cilantro, if desired.
