Make-ahead: Assemble fully, cover with foil, and refrigerate up to 24 hours before baking. Add 10 extra minutes to covered bake time. Freezer: Freeze unbaked (tightly wrapped) for up to 3 months; thaw overnight in fridge before baking. Lighter version: Replace condensed soup with a homemade roux sauce using 1 cup low-sodium broth + 2 tbsp flour + 2 tbsp olive oil, cooked until thickened. Protein swap: Rotisserie chicken, shredded turkey, or ground beef all work well. Gluten-free: Use corn tortillas and a certified GF cream of chicken soup or homemade sauce.