1. In a small skillet, saute onion in 1 tablespoon oil until crisp-tender. Add garlic; cook 1 minute longer.
2. Transfer to a 5-qt. slow cooker. Stir in 3/4 cup broth, olives, tomatoes, tapioca, lemon peel and oregano. Add chicken. Cover and cook on low for 3-1/2 to 4 hours or until chicken is tender.
3. In a large saucepan, bring remaining oil and broth to a boil. Stir in couscous. Cover and remove from the heat; let stand for 5 minutes or until broth is absorbed. Serve with chicken; sprinkle with feta cheese. Yield: 6 servings.