In a large cast iron skillet cook all of the bacon on med/high heat. Remove bacon and place on paper towels. Drain the grease into a glass jar.
Add the onions into the cast iron and cook for 5 minutes on medium heat. Then add in the mushrooms and stir. Cook for an additional 5 minutes.
In large bowl add the egg substitute, eggs, milk, hash browns, cheese, and green chilies. Season it generously with salt and pepper. Then crumble up the bacon and place it in the large bowl along with the onions and mushrooms.
Pour in a 13×9 inch greased casserole dish. Cover with foil and place in refrigerator overnight.
Preheat oven to 350 degrees.
Cook uncovered for 45-55 minutes or until center is done. You can check by inserting a butter knife and if it comes out clean then the dish is done.