In a 3-1/2- to 5-quart slow cooker place mushrooms, onion, and garlic. Place chicken on top of vegetables. In a bowl combine broth, tomato paste, wine, tapioca, dried basil (if using), sugar (if using), salt, and pepper. Pour over chicken.
Cover and cook on low-heat setting for 7 to 8 hours or on high-heat setting for 3-1/2 to 4 hours. If using, stir in fresh basil. If desired, serve over pasta. Sprinkle with Parmesan cheese. Makes 6 servings.