Preheat oven to 400 degrees.
Toss diced zucchini and corn in olive oil, oregano, salt & pepper. Spread on a baking sheet and roast for 15 minutes. Remove from oven.
Spread a layer of tortilla chips on a baking sheet. Sprinkle with layers of veggies, cheese, then more chips, and cheese, then more veggies, and chips, and cheese and bake for 10 - 15 minutes until cheese is melty.
Sprinkle with scallions & fresh cilantro. Serve with fresh tomato salsa and sour cream.