To make this Smothered Chicken with Creamed Spinach recipe gluten-free, confirm that the zesty Italian dressing mix is certified gluten-free or labeled free from gluten-containing additives. Some seasoning packets may contain wheat-based thickeners, anti-caking agents, or flavor additives, so check the label carefully. The chicken, olive oil, onion, mushrooms, cream cheese, spinach, shredded cheese, salt, and black pepper are naturally gluten-free, but packaged products should still be checked for cross-contact. Use clean utensils, bowls, skillets, baking dishes, and prep surfaces to prevent gluten contamination.