Cut the chicken breast into small pieces.
Slice the onion and bell pepper into thin strips.
Add olive oil to a pan and stir-fry the chicken breast.
Add the onion and bell pepper, and stir-fry together.
Lightly toast the tortilla on the pan, then remove.
Place the cooked ingredients, lettuce, and cheese on the tortilla.
Wrap the tortilla into a roll shape.
Cut into bite-sized pieces.