Preheat oven to 350°F. Heat 1 tablespoon of the oil in large skillet on medium-high heat. Add bell pepper, onion and zucchini; cook and stir 4 minutes or until tender-crisp. Add mushrooms and Seasoning; cook and stir 2 minutes longer.
Place 4 of the tortillas on ungreased baking sheet. Spread 1/4 of the vegetable mixture and cheese evenly on each tortilla. Top with remaining tortillas. Lightly brush with remaining 2 teaspoons oil. Sprinkle lightly with additional Seasoning, if desired.
Bake 10 minutes or just until cheese is melted. Cut into 3-inch wedges. Serve warm.