In a small bowl, combine the homemade fajita seasoning mix with cornstarch, ¼ cup of canola oil, and the juice of 1 lime. Mix until smooth.

Slice the boneless, skinless chicken breasts into ¼" thick pieces. Coat with ⅔ of the prepared seasoning mixture and marinate for at least 30 minutes.

Slice bell peppers and onion into thin strips. Toss with remaining seasoning mixture.

Heat 1 tablespoon of canola oil in a large skillet over medium-high heat and cook the seasoned vegetables for 4-5 minutes.

In the same skillet, add another tablespoon of oil and increase the heat. Cook the marinated chicken for about 4 minutes per side until golden brown.

Return the vegetables to the skillet with the chicken and heat through. Squeeze remaining lime juice before serving.

Warm the flour tortillas and spoon the chicken and vegetable mixture into the center, adding toppings as desired.