Preheat oven to 375 degrees. Grease a 9 x 13 baking dish.
Spoon chicken into a flour tortilla and add desired amount of cheese. Roll up tortilla and place fold side down in baking dish.
In a skillet on medium heat, melt butter. Whisk in flour and cook for 1 minute.
Slowly add in chicken stock until combined. Add in green chilies and sour cream and mix together.
Heat until warm. Do not boil.
Pour sauce over tortillas. Bake for 20 minute at 375 degrees.
Remove from oven add cheese and bake for 5 minutes or until melted and golden browned