Mix all seasonings together in a small bowl. Use seasoning mixture to coat chicken breasts on both sides.
Heat the oil in a large skillet over medium heat. Sear the chicken breasts for 8 minutes, without turning. Turn, and cook for a further 7 minutes. Remove chicken from skillet to a plate. Leave the chicken to rest while you sauté the vegetables.
Add sliced peppers and onions to skillet, and sauté for 8 minutes, stirring occasionally, until the vegetables begin to soften.
Slice the chicken into thin strips, add to skillet, and mix with vegetables. Add the lime juice to the skillet, stir again.
Serve the fajitas wrapped in tortillas and topped with pico de gallo (recipe follows).