Preheat oven broiler. Place pitas on baking sheets and brush each with oil. Broil for 2 minutes, or until golden brown on top, being careful not to burn them.
Remove from oven and spread sauce over pitas. Top with spinach, cheese, chicken, and artichoke hearts (if using).
Broil for 1 minute, or until cheese is melted. Garnish with basil.