Heat 5cm of oil in a small saucepan and fry the onion in batches until crispy, set aside on a paper towel lined plate.
Fry the chorizo until the fat is rendered. Remove from heat and place in a bowl.
Heat 1 tablespoon of oil in the pot. Whisk the eggs and milk together and add to the pot. Scramble until soft and creamy then remove from the heat. Add the cheese and chorizo and fold in.
Serve tortillas with eggs and topped with crispy onions, coriander, limes and hot sauce.