Preheat oven to 350 degrees. Lightly oil 9x13 inch baking dish. Add oil to skillet and brown onion, garlic and jalapeno. Add zucchini and cook 5 minute or until tender. Add spinach and corn. Cook and stir until spinach wilts. Turn off heat and add diced green chile peppers.
Dip 6 tortillas in the enchilada sauce, and place them in the prepared baking dish, overlapping as needed to cover bottom of dish. Place 1/2 of the vegetable mixture on top of the tortillas. Top with half the cheese. Layer with another 6 tortillas dipped in enchilada sauce and the rest of the vegetable mixture. Drizzle with remaining enchilada sauce. Sprinkle with remaining cheese and olives. Cover with foil and bake for 30 minutes. Uncover, and continue baking for an additional 15 minutes, or until the casserole is bubbling and the cheese is melted.