Preheat oven to 350 F and spray or butter a cast iron skillet.
In a large mixing bowl, combine cream cheese, Ranch dressing, chicken, and sour cream. Add in half of the cheddar cheese, half of the bacon, and half of the green onion. Stir to combine well.
You can use any oven safe skillet or a round cake pan, pie plate, square pan, or small casserole dish.
Leftover chicken breasts or a rotisserie chicken from the store can easily be shredded for this dip. Though you can just as easily cook up a boneless skinless chicken breast or two (thighs work as well) if that's what you have on hand.
We used cheddar cheese, but any of your favorite melty cheeses will work. Try gouda, mozzarella, Monterey Jack, Havarti, or provolone.