Heat oil in 12-inch skillet over medium-high heat. Sprinkle chicken with garlic salt, pepper and oregano. Cook chicken in oil 8 minutes, turning once, until brown on both sides; drain. Place chicken, tomatoes and artichokes in 4- to 4 1/2-quart
Cover and cook on Low heat setting 5 to 6 hours.
Cook couscous as directed on package. Stir olives into stew. To serve, spoon stew over couscous.