Cook the pasta to al dente, according to the package instructions. Immediately drain and run under cold water to stop cooking.
To a large skillet, add the chicken, enchilada sauce, and chiles. Stir everything together until evenly combined and bring the mixture to a simmer. Continue cooking, stirring occasionally, for 8-10 minutes.
Remove the skillet from heat, and stir in the sour cream until evenly combined. Stir in half the cheese, just until completely melted and the mixture's smooth.
Lightly spray a 9x13 baking dish with non stick cooking spray. Pour the chicken mixture into the prepared dish. Add the chicken mixture evenly out over top and use a spatula to stir it all together and spread it out evenly.
Sprinkle the remaining cheese evenly out overtop. Bake at 350 degrees for 15 minutes, or until the cheese has begun to turn golden brown.
Remove from the oven, and let the casserole rest for 2 minutes before serving.