Put all chicken into a non-stick skillet (break up any large pieces of chicken). Sprinkle in all the taco seasoning and prepare chicken mixture according to directions on taco packet.
Using a well heated skillet put a light coat of vegetable oil in the skillet, making sure the bottom of skillet is coated. Place a tortilla in the skillet and top with chicken, cheese, onion and peppers. Taking a large spatula, flip the tortilla to a half moon shape. Heat approximately 15 seconds and flip the tortilla so the other side can get toasted. Using a pizza cutter, slice the tortilla into slices and serve. If desired, add toppings from optional list above.