LOL just a personal preference to stay away from cream soups in my enchiladas. Not that I'm a soup snob - I just try to avoid the extra preservatives and sodium. I hope you enjoy these. You can substitute the Monterey Jack for Mexican blend of cheeses.
Preheat oven to 400 F. Lightly spray a 9 x 13 dish with cooking spray. In a medium fry pan, cook chicken and onion together in oil until chicken is just done. Add rotel tomatoes and 1/2 pkg taco seasoning.
Divide chicken mixture evenly between 8 tortillas. Add 1-1/2 tablespoons of cheese over chicken. Roll enchiladas and place seam side down in a 9 x 13 dish.
In a separate sauce pan, melt butter. Stir in flour to make a roux. Stir and cook until bubbly. Add remaining 1/2 package of taco seasoning and cumin. Gradually whisk in chicken broth then bring to a boil, stirring frequently.
Remove from heat. Stir in sour cream and green chilies. Pour sauce evenly over enchiladas. Top with 3/4 cup cheese. Bake for 20 minutes until cheese is melted and sauce around the edges of the baking dish is bubbly.
Note - this makes a lot of sauce. I put my 9 x 13 pan on a cookie sheet when baking.