Using two forks, shred the chicken into strips. Set the chicken aside.
Step 2: Sautée
Heat the olive oil in the skillet over medium heat. Add the onion and cook, stirring until the onions become translucent. Add the garlic, and cook stirring until it releases its aroma (about a minute).Stir in red peppers and green peppers. Cook stirring, until the vegetables are softened, about 3 to 5 minutes.
Step 3: Simmer
Add the chicken, tomato, bay leaf, cumin, paprika, oregano, salt, pepper, and green olives. Cook, stirring until everything has heated through.Lower the heat to medium-low, add chicken stock, cover, and let it simmer until the tomato are very soft (about 5 minutes). Stir in the tomato paste, and stir to dissolve and reduce the cooking liquid to a thick sauce.
Step 4: Serve
Remove from the stove, discard the bay leaf, season with salt and pepper to taste, garnish with cilantro or parsley, and serve.