Preheat oven to 200C/380F. S
pit and thinly slice olives. In a bowl stir together olives, goat cheese, thyme and salt/pepper to taste until combined well.
 Pat chicken dry and season well.
 Put the chicken breast halves on a cutting board and, with a sharp knife, create a pocket. Divide the goat cheese filling between pockets of both chicken breasts. In a ovenproof skillet heat oil until hot and brown chicken on both sides, about 2 minutes on each side. 
Transfer skillet to middle of oven and bake chicken until cooked through, about 20 minutes.