In a small bowl, mix the fajita seasoning with the cornstarch. Add 1/4 cup of the oil and the juice of 1 lime, whisking to combine thoroughly. If the mixture is too thick, thin it with a little water. Set aside.

Slice the chicken breasts into 1/4-inch thick slices and place them in a shallow bowl or zippered freezer bag. Pour 2/3 of the fajita seasoning marinade over the chicken, tossing to coat. Set aside.

While the chicken is marinating, slice the bell peppers and onion. Place them in a bowl or zippered freezer bag and add the remaining 1/3 of the marinade. Toss the vegetables until well coated, then set aside.

In a large cast iron skillet or heavy-bottomed pan over medium-high heat, heat 1 tablespoon of oil. Add the marinated vegetables and cook, stirring occasionally, until the onion softens and the peppers start to color, about 4-5 minutes. Transfer the cooked vegetables to a bowl.

In the same skillet, add the remaining oil and cook the marinated chicken undisturbed. Once the bottom of the chicken turns white and is browned, about 4 minutes, flip the chicken and cook for another 4 minutes until cooked through and juices run clear.

Add the sautéed peppers and onions back to the skillet with the chicken. Cook everything together for an additional 2-3 minutes to heat through. Remove from heat and finish with a squeeze of the remaining lime juice.

Serve your delicious fajitas with warm flour tortillas, pico de gallo, avocado sauce, crema, and extra lime wedges for a burst of flavor.