Combine first 6 ingredients in a small bowl; set aside.
Place a nonstick skillet coated with cooking spray over medium-high heat until hot. Add chicken and bell pepper sauté 4 minutes or until chicken is browned. Stir in 1/4 cup water, scraping pan to loosen browned bits. Stir in currant mixture, and cook chicken over medium heat 2 minutes or until slightly thick. Set chicken aside, and keep warm.
Bring 1 1/2 cups water to a boil in a medium saucepan; gradually stir in couscous. Remove from heat; cover and let stand 5 minutes. Fluff with a fork. Serve chicken and sauce over couscous. Sprinkle with walnuts.