Heat a large cast iron skillet over medium heat until hot. Add chorizo and cook, using a spoon to break it up into chunks, for 5-7 minutes until cooked through.
Remove chorizo to a bowl. Drain all but one tablespoon of the chorizo fat away – we’re going to use that to cook the onions! Return the skillet and one tablespoon of fat to the stove over medium heat.
Add onions and garlic to skillet and cook, stirring occasionally, until onions are translucent, about 3 minutes.
Add salt, pepper and tomato sauce to skillet and stir to combine.
Return the cooked chorizo to the skillet. Cook until tomato sauce is simmering, about 4 minutes. If your tomato sauce looks thin, let it cook an extra few minutes to thicken. Remove skillet from heat.
Use a spoon to make four small indents in the skillet. Crack an egg into each indent. Transfer skillet to hot oven and bake for 7-15 minutes until egg whites have set. If you like your egg yolks runny, cook them for 7-10 minutes until the whites are opaque. If you like well-done eggs, add an extra few minutes to the cook time. (To gauge egg doneness, give the eggs a poke with the back of a spoon and see how much they jiggle! Keep in mind that eggs will continue cooking in the hot skillet once you take them out of the oven).
When eggs are cooked to your desired doneness, remove the skillet from the oven. Top with Cacique ® Cotija cheese, green onions, cilantro, and sliced avocado. Serve immediately with grilled or toasted bread or warm tortillas.