HEAT oven to 425°F.
WHISK dressing mix, vinegar and oil until blended. Pour over vegetables in large bowl; toss to evenly coat. Spread onto bottom of rimmed baking sheet.
BAKE 20 min. or until vegetables are tender, stirring occasionally.
HEAT broiler. Place tortillas in single layer on baking sheet; top with roasted vegetables and cheese.
BROIL 2 min. or until cheese is melted. Roll up.