Yes, this dish makes an awesome freezer meal. Prepare the casserole but do not bake. Allow the broccoli to fully cool (and the chicken, if you're cooking it yourself) in the dish before sealing it with an air-tight lid (or tightly wrapped with plastic wrap followed by aluminum foil). Freeze for up to 3 months. Allow to thaw in the refrigerator overnight before baking. You may need to add 5-10 extra minutes in the oven if it's going in cold.