COOK tortilla in medium skillet sprayed with cooking spray on medium heat 30 sec. Turn; top with cheese and egg. Cover with lid; cook 4 min. or until egg white is almost set.
TOP with ham. Carefully fold tortilla in half, being careful to not break yolk; cook, covered, 1 min. or until ham is heated through, egg white is completely set and yolk is cooked to desired doneness.