Heat olive oil in a non-stick skillet over medium heat.
Add chorizo and cook, breaking it up with a spoon, until browned and cooked through, about 5-7 minutes. Remove chorizo from skillet and set aside, leaving drippings in the pan.
In a bowl, whisk together eggs and milk. Season with salt and pepper.
Pour egg mixture into the same skillet. Cook, stirring gently, until eggs are softly set.
Warm tortillas according to package directions.
To assemble tacos, place a portion of cooked chorizo on each warm tortilla.
Top with scrambled eggs, chopped onion, and cilantro.
Add your favorite optional toppings and serve immediately.
Notes
You can adjust the spice level by choosing a milder or spicier chorizo.
For a richer flavor, use heavy cream instead of milk in the eggs.