Preheat your oven to 375°F (190°C). In a medium pot, combine brown lentils with water and a pinch of salt. Bring to a boil, then add quinoa. Cook for about 20 minutes until very tender, then drain excess liquid.

Finely mince brown mushrooms in a food processor. In a large skillet, heat olive oil over medium heat. Sauté mushrooms for 5-8 minutes until browned and moisture has evaporated.

Transfer lentils and quinoa to a mixing bowl. Combine with sautéed mushrooms, one can of enchilada sauce, chopped green chiles, and half of the shredded cheese. Mix thoroughly.

In a baking dish, pour half of the remaining enchilada sauce to coat the bottom. Arrange corn tortillas over sauce, overlapping slightly. Spoon half of the filling mixture on top.

Place another layer of tortillas over the filling. Drizzle with more enchilada sauce, then top with remaining filling. Finish with more tortillas, sealing flavors and pouring remaining sauce over.

Sprinkle remaining shredded cheese over the top. Cover with aluminum foil and bake for 25 minutes.

Remove foil and switch oven to broil. Broil for an additional 1-3 minutes until cheese is bubbly and golden brown.

Let the casserole rest for 10 minutes before serving. Garnish with optional toppings as desired.