Coat the bottom of an oblong baking dish with olive oil then sprinkle with garlic and chilli flakes.
Arrange the chicken breasts in bottom of the dish then pour spaghetti sauce over chicken. Sprinkle basil over spaghetti sauce then top with half the mozzarella cheese, followed by half the Parmesan cheese. Sprinkle on the croutons then top with the remaining mozzarella cheese and remaining Parmesan cheese.
Bake in preheated oven until cheese and croutons are golden brown and the chicken is no longer pink inside, about 35 minutes to an hour, depending on the shape and thickness of your chicken breasts.