To a large skillet, add olive oil and sauté the bell peppers over medium heat. Cook the peppers for about 3-5 minutes.
Season the chicken breast with the fajita seasoning, on both sides, and place the chicken into the skillet. Cook until the chicken is cooked throughout, and the peppers are soft.
Reduce heat to low and place a slice of Borden Cheese on top of each chicken breast. Cover with a lid until the cheese is melted and remove from the heat.
Separate the whole wheat buns and put together the Chicken Fajita Sandwiches. Serve warm and Enjoy!