Pound each chicken breast between sheets of plastic wrap with a meat mallet until thin. Spread a tablespoon of pesto over each chicken breast, then place olives and feta cheese in the centre of each breast. top with basil leaves, and fold the ends of the chicken breaks in towards the centre to form a stuffed ball.
Place the chicken open side down in a lightly oiled baking dish.
Coat the tops of the chicken with remaining pesto sauce and bake in a 400F oven for 30 minutes.