Saute the peppers and onions in olive oil over medium-high heat for 5 minutes until softened. Season with salt and pepper. Stir in green salsa.
Spray a baking dish with oil.
Layer half the tortillas in a 9x13-inch baking dish. Top with half the pepper-onion mixture and 1 cup of cheese. Top the cheese with 4 eggs, salt, and pepper.
Layer the remaining tortillas. Top with the remaining pepper-onion mixture and 1 cup of cheese.
Create 6 wells in the casserole. Crack one egg into each well. Top with salt and pepper.
Bake for 25-30 minutes until the eggs are set and the tortillas are crispy at the edges.
Remove the casserole from the oven. Top with avocado, cilantro, sour cream, and tomatoes.