Place the chicken in a 3-qt. slow cooker; sprinkle with garlic powder, onion powder and pepper. Top with soups. Cover and cook on high for 3-4 hours or until chicken is no longer pink. , Stir in the cheese, olives and pimientos if desired. Cover and cook until cheese is melted. Meanwhile, cook fettuccine according to package directions; drain. Serve with chicken; top with coarsely ground pepper if desired.