Step 1

In a medium bowl, mix together all the ingredients for the marinade.Mix the chicken into the bowl and let it marinade for 30 minutes at room temperature or cover it and place it in the refrigerator for up to 4 hours.Heat 2 tablespoons of the the oil in a large cast iron skillet set over medium-high heat

Step 2

Working small batches add the chicken to the pan and sauté until the chicken is cooked all the way through.When the chicken is cooked add the remaining 2 tbsp oil to the pan and turn up the heat to high

Step 3

Once oil is smoking sauté the red onions and bell peppers on until they are just tender and turning dark brown in some spots

Step 4

Add chicken back into the pan and mix everything together.Serve the fajitas with warm tortillas, lime, cilantro, avocados and cheese if desired.