Grease a 9x13 inch baking dish.
Cook the chorizo in a large skillet over medium heat 5 to 6 minutes or untill cooked through, stirring occasionally and breaking up pieces with wooden spoon. Drain grease, if necessary.
Beat eggs and milk in a large bowl with whisk until blended.
Cut muffins into quarters.
Add 1-1/2 cups of the cheese to bowl and muffins, separating all pieces.
Gently fold in chorizo.
Pour into dish, pressing muffins into egg mixture.
Sprinkle with remaining cheese.
Cover and refrigerate for 6 hours or overnight.
Heat oven to 350 degrees F.
Bake, uncovered, for 45 minutes or until light golden brown and heated through. Let stand 10 minutes, Top with tomato, avocado, and cilantro.
Serve with salsa