Crumble the chorizo in a large skillet and cook over medium heat with the chopped onion and green pepper. Cook for six to eight minutes, stirring occasionally, until the sausage is fully cooked. Drain and set aside.
In another skillet, heat the butter over medium heat. Scramble the eggs until they are just set. Remove them from the heat and mix in the sausage, onion and pepper, plus ⅓ cup each of the cheddar and pepper jack cheese.
Spread ½ cup of the enchiladas sauce into a greased 11x7-inch baking dish. Spoon 3 tablespoons of the egg mixture into each tortilla and then them roll up. Place it seam side down in the prepared dish. Continue until all of the tortillas are filled.
Pour the remaining enchilada sauce over the top of the enchiladas and sprinkle with the remaining shredded cheeses. Bake uncovered at 350ºF until the enchiladas are heated through, about 25 to 30 minutes. Garnish with the green onion.
