In a medium-sized pot or frying pan, heat a swirl of your choice of oil and add diced onion, ground beef, and Italian sausage. Break up the pieces and cook on medium/high heat, stirring frequently. Drain off excess fat and return to burner on low, adding in seasonings and sour cream. Remove from heat.
Spray a 9x13 pan or two smaller pans with non-stick spray.
Take each tortilla and spread on 2-3 tablespoons of refried beans. Just eyeball it, keep it simple. Add a generous scoop (1/3 cup) of meat mixture, fold in two sides, and place burrito into pan, seam side down. Continue until tortillas are used up; if you have additional fillings, go ahead and spread them across the top.
Pour green chile sauce over the filled tortillas, spreading it over all of the center and into the edges. Top with cheese.
Cover with foil and bake at 350° for 30 minutes until hot and bubbly. Let set 10 minutes, top with tomatoes, lettuce, salsa, and more cheese, if desired.