Rub the oil and seasonings into the chicken breasts and place on a baking tray.
Cut parallel lines into the chicken breasts, roughly 4/5 of the way down - make sure you don't cut all the way through! In each cut place a slice of each coloured pepper and red onion.
Grill on a high heat for roughly 15/20 mins, until the chicken is cooked through and the peppers and onion are soft.
Take out and sprinkle with cheese then place under the grill for another 5 minutes.
Serve with charred tortillas, a squeeze of lime and a sprinkle of coriander.