Preheat oven to 425°.
Combine Broccoli, carrots, and mushrooms. Drizzle with olive oil; season to taste with salt and pepper.
Spread vegetables in a single layer in a shallow baking dish; roast in preheated oven for 30-40 minutes (ovens vary). Stir once while cooking.
Remove vegetables from oven; reserve.
Reduce oven heat to 350°.
Prepare mashed potatoes. Once completed, stir in vegetables while potatoes are still warm.
Heat tortillas (one at a time) on both sides until pliable (bendy).
As each tortilla is warmed, put about 1/3 cup of vegetable mixture into each. Top with a sprinkle (2 tablespoons) of cheese and roll tortillas; place "seam side down" in 9x13 baking dish.
When all tortillas complete pour any enchilada sauce over them. Top with any remaining cheese.
Bake at 350° for 20-30 minutes.