In a small bowl, combine well all the spices chili powder, smoked paprika, ground cumin, granulated garlic, and salt.
Preheat the skillet over medium heat. Add olive oil to the pan. Season the chicken with the fajita seasoning, saving about a fourth of it for the vegetables.
Cook the chicken for about 5-7 minutes on each side, or until the internal temperature reaches 165 degrees.
While the chicken cooks, cut onion and all of the peppers into slivers.
Once chicken is cooked, remove and set aside. Add in vegetables and sprinkle them with the remaining seasoning.
Saute the veggies until they caramelize (about 10 minutes), stirring occasionally.
While the vegetables cook, slice the chicken into thin strips. As the vegetables are finishing, add your chicken into the skillet and mix thoroughly.
Remove from heat. Heat up tortillas in the microwave or on the stovetop and fill each one with the fajita mixture.
Feel free to garnish with sour cream, shredded Mexican cheese, salsa, any of your favorite toppings