Spray each piece of chicken with oil then sprinkle with taco seasoning. Place on a baking rack over a parchment paper covered baking sheet. Bake in the oven for 25 minutes.
In another sauce pan over medium heat, add butter. In a small bowl, whisk together cornstarch, seasonings and chicken broth. Stir broth into melted butter and next whisk in sour cream. Once combined, add jalapenos and cook for 5 minutes, stirring occasionally. Sauce should begin to thicken.
Remove chicken from oven and chop into small pieces. Combine in a bowl with ¾ of the green onions and chorizo.
Ladle a thin layer of sauce into a 13x9 baking dish. Fill each tortilla with a portion of the cooked chicken mixture and roll it up. Line tortillas up in the baking dish. Poor remaining sauce evenly over top of tortillas. Sprinkle with cheese and remaining green onions. Bake in oven for 30 minutes. Let sit at least 5 minutes before serving.