In a skillet over medium-high heat, add 1 tablespoon of olive oil. Sauté the sliced bell peppers and onion until they are tender and slightly caramelized, about 5-7 minutes. Stir in the fajita seasoning mix and cook for another 1-2 minutes. Remove from heat and let it cool slightly.
While the vegetables are cooling, prepare the chicken breasts. Using a sharp knife, carefully slice a pocket into each chicken breast without cutting all the way through.
Season the chicken breasts with salt, pepper, and the remaining tablespoon of olive oil.
Stuff each chicken breast with the sautéed peppers, onion, and a generous amount of shredded cheese. Pin the opening closed with toothpicks if necessary.
Place the stuffed chicken breasts in a baking dish. If desired, sprinkle a little extra fajita seasoning on top for added flavor.
Bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and the internal temperature reaches 165°F (75°C).
Once cooked, remove the chicken from the oven and let it rest for 5 minutes before slicing.
Serve your fajita stuffed chicken garnished with chopped cilantro, alongside lime wedges for squeezing over the top.
Notes
Let the chicken rest before slicing for juicier meat.