Melt a stick of butter in the bottom of a 9x13 casserole dish.
Add the rotisserie chicken to the bottom of the pan.
Mix together 2 cups of milk and 2 cups of Red Lobster Cheddar Bay biscuit mix.
Add 1 can of cream of chicken soup and 2 cups of chicken stock, along with the seasoning packet from the rotisserie chicken.
Pour the mixture over the chicken.
Bake uncovered at 350°F for 45 minutes.
Let it sit for about 15 minutes before serving.
