- Begin by preheating your oven to 350°F. 
- Make sure your chicken breasts are generously seasoned with salt and pepper. 
- Place the chicken in a baking dish and roast for about 35 to 40 minutes until cooked through. 
- Allow them to cool and then shred the meat into bite-sized pieces. 
- In a large pot, heat olive oil over medium-high heat. 
- Add the chopped onions and minced garlic. 
- Let them sauté until soft and translucent. 
- Add the diced bell peppers, red pepper flakes, and chili powder to the pot. 
- Cook for about a minute, stirring frequently, to release their flavors. 
- Pour in the tomatoes, chicken stock, and shredded chicken. 
- Stir well and let the mixture simmer for 30 minutes to an hour. 
- Adjust seasoning with salt and pepper as needed.