Cut the chicken breast into small pieces.
Slice the onion and bell pepper into thin strips.
Stir-fry the chicken breast in olive oil in a frying pan.
When the chicken is cooked, add the onion and bell pepper and stir-fry together.
Place the cooked ingredients and cheese on a tortilla.
Fold the tortilla in half and cook on both sides in a pan until the cheese melts.
Cut into bite-sized pieces and serve on a plate.