In a large bowl, mix chopped chicken and 1 cup of Monterey Jack cheese.
Fill 1/8 of chicken and cheese mixture into each taco shell, and roll up. Place taco shells side-by-side in baking dish with the "seam" of the shell on the bottom. Feel free to get creative with placement, and try to cover the entire dish!
In a small saucepan, melt butter over medium heat. Whisk flour into butter and cook for 1 minute.
Slowly add chicken broth while continuing to whisk. Cook for 10 minutes, or until sauce thickens.
Remove sauce from heat, stir in sour cream and chilis.
Pour sauce over enchiladas in dish
Top with remaining cheese and bake for 22 minutes. Then switch on the broiler for 3 minutes to brown top of cheese.