1. 1. Preheat the Oven: Set your oven to 375°F to ensure even cooking.

2. 2. Prepare the Vegetables: If using frozen spinach, thaw it completely and squeeze out any excess water. For fresh broccoli, give it a quick boil for 1-2 minutes until bright green, then drain.

3. 3. Combine the Ingredients: In a large bowl, mix together the cooked chicken, crispy bacon, prepared vegetables, minced garlic, ranch dressing, and half of the mozzarella and cheddar cheeses. Add the optional ranch seasoning if desired.

4. 4. Transfer to a Baking Dish: Pour the mixture into a 9×13-inch casserole dish.

5. 5. Top with Cheese: Sprinkle the remaining mozzarella and cheddar cheeses evenly over the top of the casserole.

6. 6. Bake to Perfection: Pop the casserole in the preheated oven and bake for about 15 minutes, or until the top is hot and bubbly.

7. 7. Serve and Enjoy: Remove the casserole from the oven, let it cool slightly, and then dig in!