Preheat oven to 400°F.
In a large mixing bowl, thoroughly combine muffin mix, eggs, milk, and cheeses.
Remove chorizo from its casing and place in a skillet over medium heat. Cook for 4-5 minutes, crumbling with a spatula throughout.
Stir cooked chorizo into remainder of mixture. Pour evenly into a cooking sprayed muffin tray. Should make 10-12 muffins.
Bake in 400°F oven for 18-20 minutes.
Remove and let cool for at least 20 minutes before removing from muffin tray.