Add half the onions and all the poblano pepper and cook, stirring, until softened and start to add color, about 6-8 minutes.
Add sausage and cook, stirring and breaking up with a spoon. Cook until sausage is fully browned, about 10 minutes. Stir in chipotle pepper and remove from heat.
Transfer chorizo to a warm bowl. Add remaining onion and fresh cilantro.
Serve immediately with tortillas, cilantro, sour cream, cheese, and avocado.