Preheat oven to 180 degrees C. Grease a 22x33cm baking dish.
Sprinkle 1 teaspoon parsley and 1 teaspoon basil evenly over the bottom of the baking dish. Arrange chicken breast halves in the dish, and sprinkle evenly with garlic slices. In a small bowl, mix together the remaining parsley, the remaining basil, the salt and chilli flakes; sprinkle over the chicken. Top with tomato slices.
Bake covered in the preheated oven 25 minutes. Remove cover and continue baking 15 minutes, or until chicken juices run clear.