Heat the oil in a large frying pan over medium-high. Add the potatoes, onion, garlic powder and onion powder to one side of the pan and season with salt and pepper. Add the chorizo on the other side of the pan and saute, breaking up with the back of a spoon, for 5 minutes or until browned. Turn over the potatoes after a couple of minutes so they get brown on both sides.
Combine the eggs, milk, 1 tablespoon coriander, salt and pepper in a bowl. Reduce heat and pour egg mixture into the pan. Stir eggs for about 3 minutes or until they are very softly set. Remove from the heat.
Spread out the warmed tortillas and divide potato, chorizo, and egg mixture among them. Sprinkle with the remaining coriander. Top with the cheese and salsa.