Preheat oven to 425°. Spray baking dish with nonstick cooking spray.
Add the 3 cups traditional rotisserie chicken, shredded, 2 cups mixed frozen vegetables, and 2 cans gluten free cream of chicken soup into a large pot. Cook on medium heat until heated through, about 5 minutes.
While chicken mixture is heating, stir together 1 cup cold water, ½ cup shredded sharp cheddar cheese, 1 box Gluten Free Red Lobster Cheddar Bay Biscuit Mix. Don't overmix. You can use a utensil to chop up the mix to make it crumbly. Save garlic herb blend packet for after baking.
Pour chicken mixture into 9" baking dish. Scoop spoonfuls of biscuit mix on top of the pot pie mixture, covering the top.
Place dish in oven and bake for 20-22 minutes or until biscuits are golden brown. You will need to check biscuits to make sure all the dough is fully baked. While baking, melt ¼ cup butter and add garlic herb blend packet from biscuit mix box and stir until blended.
Take the dish out of the oven once the biscuits are fully baked and spoon or brush the garlic butter mix onto the top of the baked biscuits.
Let the dish rest for approximately 15 minutes and then serve.