In a mixing bowl, combine the sliced chicken, olive oil, chipotle chili powder, cumin, smoked paprika, lime juice, salt, and pepper. Toss well to ensure all chicken pieces are evenly coated.
Cover the bowl and marinate in the refrigerator for at least 30 minutes to allow the flavors to meld.
After marinating, heat a large skillet over medium-high heat. Add the marinated chicken to the skillet. Cook for about 5-7 minutes or until the chicken is browned and fully cooked, stirring occasionally.
Once the chicken is cooked, add the sliced red and yellow bell peppers, and red onion to the skillet. Sauté for an additional 3-5 minutes until the vegetables are slightly softened but still crisp.
Remove the skillet from heat and taste for seasoning. Adjust if necessary.
Warm the flour tortillas in a separate pan or microwave for a few seconds until soft.
To serve, place a generous portion of the chicken and vegetable mixture on each tortilla. Top with fresh avocado slices, a dollop of sour cream, and a sprinkle of cilantro.
Roll up the tortillas and enjoy your flavorful fajitas!