Marinade the chicken, olive oil, garlic and chilli powder together for 15 minutes while the oven is heating up.
Then place on a small roasting tray and cook for 10 minutes.
Meanwhile peel, halve and crush the avocado with a fork, and season.
Open the rolls leaving one side sealed, then warm in the oven. Layer in the avocado, tomato and then the chicken. Top with some rocket and drizzle the lovely hot juices from the tray over the top. Then serve.