Preheat the oven to 350 degrees F (175 degrees C).
Lay Tortilla (12) flat on a baking sheet and put them in the oven for a few minutes, turning once, until they seem "stale" and a bit leathery.
Slice tortillas into quarters.
Heat 1/3 cup Vegetable Oil (1/3 cup) in a deep, heavy-bottomed skillet over medium-high heat.
Add a single layer of tortilla wedges and fry until lightly brown, but not crisp, they should still bend without breaking. Drain on paper towels. Repeat until all tortillas are fried.
In a deep pot, boil Tomatillo (1 pound) and Serrano Chili (1) in salted water until tender, about 10-15 minutes.
Transfer the cooked tomatillos and chiles to a food processor and purée along with the Yellow Onion (1), Garlic (1 clove), and Fresh Cilantro (6 sprig) until smooth but not liquified. It should still have a bit of texture - like tomatillo salsa. Season with Salt (to taste).
Once the Vegetable Oil (1 tablespoon) is hot, add 2 1/2 cups of the tomatillo mixture to the pan to fry it. Stir frequently for about 5 minutes, until the cilantro darkens and the sauce thickens a bit. Add the Chicken Stock (2 1/4 cup) and bring to a boil. Reduce heat and simmer until the sauce thickens enough to coat the back of a spoon.
Meanwhile, add the Spanish Chorizo (8 ounce) to a skillet over medium heat, and cook until browned and crispy. Set aside to drain on paper towels.
In a separate skillet, heat up some additional oil. Fry the Egg (4) until whites are set and yolks are still runny. Set aside.
Once sauce is ready, add chips in a single layer, turning to coat with sauce on both sides. When chips have softened slightly and are pliable, but not falling apart, remove to serving dishes. Repeat with remaining chips.
Top chips with chorizo, fried eggs, and Cotija Cheese (to taste) if desired. Garnish with Avocado (1) and Fresh Cilantro (to taste).