These Easy Chicken Tostadas can be gluten free very easily, but it is important to confirm that each packaged ingredient is certified gluten free. Pay special attention to the tostada shells or corn tortillas, refried beans, cooked chicken fajitas, salsa, cheese, sour cream, and any garnish or seasoning blends, since some brands may contain hidden gluten or be processed in facilities with cross-contact risks. If you are preparing this recipe for someone with celiac disease or a strong gluten intolerance, make sure your baking sheet, skillet, utensils, serving plates, and work surfaces are thoroughly cleaned before use.