1. Spoon 2 tablespoons sour cream into each crust, spreading evenly on bottom. Sprinkle 2 tablespoons chocolate chips over sour cream. Sprinkle 1/4 cup marshmallows over chocolate chips.
2. Preheat grill to medium-low. Place pies on grill; cover with 9×13-inch metal cake pan until marshmallows and chocolate are melted, checking frequently, about 5 minutes. Serve hot.