PREHEAT oven to 425°F. Beat dressing mix, vinegar and oil with wire whisk until well blended. Pour over vegetables in large bowl; toss lightly. Spoon into 15x10x1-inch baking pan. Bake 20 min. or until vegetables are tender, stirring occasionally.
COVER tortillas with vegetable mixture; sprinkle with cheese. Place in single layer on on baking sheet.
BROIL 2 min. or until cheese is melted. Roll up.