In skillet with small amount of cooking oil over medium heat, cook ground turkey and onion until turkey is cooked through. Drain grease (if any). Transfer to bowl and add sour cream, corn and 1/4 cup of the enchilada sauce.
In a 9x13 baking dish, spray lightly with non-stick cooking spray and coat bottom with 1/3 cup enchilada sauce.
In each tortilla, spoon 2 tbsp of meat mixture and 1 tbsp of cheese and roll tortilla. Place in baking dish seam-side down.
Once all enchiladas are in baking dish, pour remaining enchilada sauce over, making sure it is spread well. Sprinkle remaining cheese on top. Allow to cool (if not already) then wrap and freeze.