Cook chicken if raw. Cube or shred chicken.
Combine mozzarella and parmesan, set aside.
Combine breadcrumbs, oil, and garlic salt.
Spray freezer-proof baking dish (use disposable if you plan to give this meal away)
Evenly spread the cooked chicken on the bottom of a 10x13 dish.
Pour marinara sauce over top, smooth out with spoon or rubber spatula.
Sprinkle cheese mixture evenly over top of sauce.
Sprinkle breadcrumb mixture on top.
Cover with heavy-duty aluminum foil.
Thaw in fridge overnight.
Bake covered at 350 degrees for 40-45 minutes.
Once cooked through and bubbly, remove foil and broil for 2-3 minutes to brown breadcrumbs.