Prep Time 20 minutes minutes
Cook Time 1 hour hour 5 minutes minutes
Total Time 1 hour hour 25 minutes minutes
Three days would be the max I would store the unbaked dish because you are kind of at the mercy of the defrosted spinach and precooked chicken. If you do plan to store it that long, make sure it's airtight and in the back of the fridge where it's as cold as possible.