Combine mushrooms and red onion in food processor and pulse until all ingredients resemble ground beef. Combine with the ground beef in a large saute pan and cook over medium high heat until the meat has browned and the liquid has cooked off of the mushrooms. Add taco seasoning and a couple tablespoons of water, stir, and cook until water has evaporated. Remove from heat.

To assemble taco casserole, add chips to the bottom of a 13x9 casserole dish. Crush with hands. then, layer remaining ingredients. It doesn't really matter what order you choose, but I always prefer the cheese to be on top along with the fresh jalapeno.

Serve hot, garnish with sour cream and cilantro, and serve with sliced avocado and Cilantro Lime Slaw.