Sprinkle 1/4 teaspoon pepper and salt evenly over chicken.
Heat oil in a large nonstick skillet coated with cooking spray over medium heat.
Add chicken; cook 5 minutes on each side or until browned.
Remove chicken from pan; keep warm.
Add onion to pan; saut 5 minutes or until tender.
Add garlic; saut 1 minute.
Add 1/2 cup broth and next 3 ingredients. Return chicken to pan; bring to a boil. Cover, reduce heat, and simmer 30 minutes or until chicken is done. Stir in remaining 1/4 teaspoon pepper and parsley.
Meanwhile, bring remaining 1 1/2 cups chicken broth to a boil in a medium saucepan; gradually stir in couscous.
Remove from heat; cover and let stand 5 minutes. Fluff with a fork.