Stir together Bisquick mix and onions in small bowl; stir in milk just until moistened. Drop dough by rounded tablespoonfuls onto hot chicken mixture. Cover and cook on high heat setting 45 to 50 minutes or until toothpick inserted in center of topping comes out clean. Serve immediately. Note: This recipe was tested in slow cookers with heating elements in the side and bottom of the cooker, not in cookers that stand only on a heated base. For slow cookers with just a heated base, follow the manufacturer’s directions for layering ingredients and choosing a temperature.