Preheat the oven to 180ºC. In a large bowl mix together the chicken, peppers and onion. Add the oil and fajita seasoning and toss so it is all coated. Place on a roasting tray and cook in the oven for 20 - 25 minutes or until the chicken is cooked through. Prepare the jacket potatoes following the on pack instructions.
Cut each potato in half, put a portion of filling on the top. Serve warm.
Mix it up with beef strips instead of chicken. Why not try a Mexican stew topping by adding tinned tomatoes and black beans to the chicken and peppers.