In heavy skillet, heat 2 Tsp. oil over med-high heat, cook apples, onion and thyme for about 4 minutes or just till tender-crisp. Remove to bowl and set aside. Heat remaining oil in skillet, cook chicken, turning once for 2 to 3 minutes or till golden brown. Reduce heat to medium low. Set 1 Tbs. apple juice aside, pour remaining apple in skillet along with vinegar. Cover and simmer 6-8 minutes or till chicken is no longer pink inside. With slotted spoon, remove chicken to platter, keep warm. Combine cornstarch with reserved apple juice; stir into skillet and cook over high heat, scraping up any browned bits for 2 minutes or till thickened. Return apple mixture to pan and heat through, season with salt and pepper. Spoon around cooked chicken.