Heat 2 tablespoons oil in a skillet over medium-low heat. Cook chicken until no longer pink in the center but not browned, about 15 minutes. Transfer chicken to a dish.
Heat 1 tablespoon oil in the same skillet over medium heat. Add pine nuts; cook and stir until lightly browned, 3 to 5 minutes. Remove pine nuts to another dish. Heat 1 tablespoon oil in the skillet; cook spinach until wilted, about 3 minutes. Transfer spinach to a separate dish.
Heat 2 tablespoons oil in the same skillet. Add couscous; cook until lightly browned, about 3 minutes. Pour in chicken broth; bring to a simmer. Cover and reduce heat to low. Cook until couscous is tender, about 12 minutes. Uncover; add parsley and pepper. Stir. Layer couscous, chicken, spinach, and pine nuts onto a plate in that order.