Add the fajitas seasoning ingredients to a small mixing bowl and stir together.
Generously sprinkle the fajita seasoning on both sides of the chicken and use your fingers to press it into the chicken.
Heat the oil in a large skillet over medium heat. Sear the chicken breasts for about 7-8 minutes on each side.
While your chicken is cooking, cut the bell peppers and onion into thin slices.
Once the chicken has finished cooking, remove it to a plate and let it rest for a couple of minutes. Add the bell peppers and onion to the same skillet over medium heat and saute for 4-5 minutes, stirring frequently.
When the bell peppers are just about done sauteing, slice the chicken breasts into strips.
Add the chicken back into the skillet, add a squeeze of fresh lime juice and stir everything together.
Serve immediately with tortillas and extra toppings such as sour cream, pico de gallo and guacamole.