Preheat oven to 300 degrees F. Pit and thinly slice olives.
In a small bowl stir together olives, goat cheese, thyme and salt and pepper to taste until combined well.
Pat chicken dry and season with salt and pepper.
To form a pocket in chicken for filling: Put a chicken breast half on a cutting board and beginning in middle of 1 side of breast half, horizontally insert a sharp thin knife 3/4 of the way through the center.
moving knife in a fanning motion to create a picket.
Form pocket in remaining breast half in the same manner.
Divide filling between pockets and spread evenly with a finger.
It might be helpful to close the opening with a toothpick or two.
Just remember to remove them when the chicken breasts are served.
In a small heavy ovenproof skillet, heat oil over moderately high heat until hot but not smoking and brown chicken, skin side down about 2 minutes.
Turn chicken over and brown other side about 2 minutes more.
Transfer skillet to middle of oven and bake chicken until cooked through, about 15 minutes.