In a small bowl, combine olive oil, lime juice, cumin, chili powder, red chili pepper flakes, paprika, garlic powder, salt, and pepper. Set aside.
Place chicken breasts, bell peppers, yellow onion, and red chili pepper in a bowl.
Pour marinade over the chicken and vegetables. Cover with plastic wrap and marinate in the refrigerator for 10 minutes.
While the chicken and vegetables are marinating, prepare the guacamole. Peel, remove the pit, and mash the avocados. Stir in the remaining guacamole ingredients. Season with salt and pepper to your taste. Set aside.
In a large skillet, heat 1 tbsp olive oil over medium-high heat. Add the chicken breasts and cook for about 8 5 minutes on each side until cooked through. Chicken breasts are ready when the internal temperature reaches 165°F.
Transfer the cooked chicken breasts to a plate. Let rest for a few minutes. Then, cut into strips.
Add the vegetables to the same pan. Cook for 5 minutes or until softened. Return the chicken strips to the skillet with the vegetables. Stir and cook for a few minutes more. Serve warm with tortillas and top with guacamole. Squeeze more lime juice if desired. Enjoy!