Coat a large nonstick skillet with cooking spray; place over medium-high heat until hot. Add carrot, mushrooms, celery, peas, and onion. Saute 5 minutes or until vegetables are tender.
Combine soup, water, pepper, and thyme in a medium bowl; stir well. Add vegetables and cooked chicken, stirring well.
Spoon chicken mixture evenly into 6 (8-ounce) round baking dishes coated with cooking spray.
Place flour in a small bowl; cut in margarine with a pastry blender until mixture is crumbly. Sprinkle milk (1 tablespoon at a time) evenly over surface, stirring with a fork until dry ingredients are moistened. Drop dough evenly by spoonfuls onto chicken mixture. Bake at 425° for 15 to 18 minutes or until crusts are golden.