Heat a little olive oil in a frying pan over a gentle heat. Add the spring onions and chorizo and cook for a few minutes until the chorizo is nicely crisp.
Put the eggs in a saucepan and add the butter. Heat gently, stirring continuously until the eggs are scrambled to your liking. Season with salt and pepper, then add the chorizo and stir gently to combine.
Meanwhile, warm the tortillas in a low oven until nicely pliable.
To assemble the burritos, spread each tortilla with a dollop of chipotle ketchup, followed by the scrambled egg, then top with a dollop of guacamole. Roll it up and serve.