Preheat the oven to 350 degrees. Lightly mist a 9x13 casserole dish with cooking spray and set aside.

Place the butter in a medium saucepan and bring over medium-low heat until the butter is melted. Add the flour, salt and black pepper to the butter and stir to combine. Add the milk a little at a time and whisk the flour mixture into the milk each time until smooth. Turn the heat up to medium and add the shredded cheeses. Whisk together and then whisk on and off for 3-5 minutes until smooth and thickened and remove from heat.

*Place the broccoli florets in a microwave-safe bowl and cover the bowl with a damp paper towel. Microwave for 2 minutes on high. (*You can otherwise steam the broccoli florets if preferred)

Place the chicken, broccoli, and cheese sauce in the baking dish and stir together until combined. Add the biscuit pieces and stir in to coat. Bake for 40 minutes until the casserole is hot and the biscuits have bubbled up. Let cool for 5-10 minutes. Slice into 6 pieces and serve.