In a bowl, toss the shredded chicken with the cumin, garlic powder and smoked paprika. Set aside.
Preheat oven to 400˚F.
In a saucepan over medium heat, melt the butter. Whisk in the flour and cook until smooth.
Slowly add the chicken stock, whisking constantly to remove any lumps. Continue cooking until thickened.
Remove from the heat. Stir in the sour cream, chiles, cayenne pepper, salt and pepper until thoroughly combined. Set aside.
Divide the chicken evenly among the eight tortillas. Fill the tortillas by placing the chicken in the cente. Sprinkle 2 tablespoons shredded cheese and then rolling the tortilla around the filling to close.
Place the tortilla seam side down in a 9x13 inch baking dish coated with cooking spray. Continue to assemble the remaining tortillas.
Pour the sour cream enchilada sauce over the enchiladas and sprinkle with the remaining cheese.
Bake the chicken enchiladas for 30 minutes or until golden brown and bubbling.
Allow the enchiladas to rest for 5 minutes so the sauce can set before serving.
Top with cilantro, chopped tomatoes, salsa and sour cream, if desired.
To freeze, assemble the chicken enchiladas and cover with plastic wrap. Cover, again, with foil and freeze for up to 3 months.