Keep the dozen rolls attached to each other. Cut them in half with a sharp bread knife.
In a large bowl, mix together the rotisserie chicken, cooked bacon and ranch dressing until well combined.
In a smaller bowl or glass measuring cup, whisk together the melted butter, bacon grease, ranch seasoning and Italian seasoning. You can use 4 tablespoons of butter instead, if you don't want to use the bacon grease.
Using a silicone pastry brush, put a light coating of the butter mixture in the bottom of a 9x13 glass baking dish.
Place the bottom half of the rolls in the buttered dish.
Top evenly with four slices of the cheese.
Spread the chicken mixture evenly atop the first layer of cheese.
Place the remaining four slices of cheese on top of the chicken mixture. Then place the top half of the rolls on top of the second layer of cheese.
Evenly coat the top of the sandwiches with the remaining butter mixture.
Cover the dish tightly with foil. Bake the sliders for 18-20 minutes, or until the cheese is completely melted. Serve immediately.