Place 1/2 cup olives, 1/2 cup dried plums, oregano, brown sugar, capers, oil, garlic, salt and pepper in a food processor; process until smooth. Transfer mixture to a 4-qt. slow cooker. Place chicken in slow cooker. Cook, covered, on low 4-5 hours or until chicken is tender., Chop remaining olives and dried plums. Remove chicken from slow cooker; keep warm. Stir chicken broth, parsley, wine, lemon juice and remaining olives and plums into olive mixture. Serve with chicken and couscous.