Preheat your oven to 350°F (175°C). This will ensure that your casserole cooks evenly.
In a large skillet over medium heat, add a splash of oil. Once hot, add the cubed chicken and season with taco seasoning. Cook for about 5-7 minutes, or until the chicken is no longer pink in the center.
In a mixing bowl, combine the ranch dressing, chicken broth, and heavy cream. Stir well until fully mixed.
In the skillet with the cooked chicken, add the cooked pasta and spinach. Pour the prepared sauce over the mixture and stir until everything is evenly coated.
Pour the entire mixture into a greased baking dish, spreading it evenly.
Place the casserole in the preheated oven and bake for 25-30 minutes, or until bubbly and golden on top.
Once baked, remove from the oven and let it cool for a few minutes before serving. Enjoy your Chicken Ranch Casserole with a sprinkle of fresh herbs or grated cheese on top if desired.