Step 1: Prepare the Oven, Pan, and Biscuits - Preheat your oven to 350°F and lightly coat a 9x13 inch baking dish with nonstick cooking spray. While the oven heats, open the biscuits and cut each one into about four to six smaller pieces. I lean toward smaller pieces because thick chunks of dough can stay undercooked in the middle of a creamy casserole. Set the pieces aside while you make the filling.
Step 2: Mix the Creamy Ranch Base - Add the softened cream cheese, sour cream, ranch dressing, ranch seasoning, and milk to a large mixing bowl. Stir until the mixture is mostly smooth. It does not need to look absolutely flawless, so do not spend ten minutes chasing every little speck of cream cheese around the bowl. Once it bakes, those small soft pieces will melt into the sauce. You are mainly looking for a mixture loose enough to coat the chicken and biscuits.
Step 3: Add the Chicken, Bacon, and Cheese - Stir the cooked chicken, crumbled bacon, and 1 cup of shredded cheddar into the ranch mixture. Keep stirring until the chicken is evenly coated and the bacon and cheese are spread throughout the bowl. I like to break apart any large clumps of chicken at this point because smaller pieces give you a little bit of everything in each scoop.
Step 4: Fold in the Biscuit Pieces - Add your cut biscuit pieces to the bowl and gently fold them into the chicken mixture. Try to get some of that creamy ranch coating around every piece. You do not need to stir aggressively because you want the biscuits to keep some of their shape. Transfer everything to the prepared baking dish and spread it into an even layer. Sprinkle the remaining 1/2 cup cheddar over the top.
Step 5: Bake Until Golden and Bubbling - Bake the casserole uncovered for 30 to 35 minutes. You are looking for a golden top, bubbling creamy filling around the edges, and biscuit pieces that are cooked through instead of doughy in the center. Because ovens and baking dishes can vary, start checking around the 30 minute mark. If the top is browning faster than the biscuits are cooking, loosely cover the dish with foil and let it finish baking.
Step 6: Rest, Garnish, and Serve - Take the casserole out of the oven and give it about five minutes to rest before you scoop into it. That short rest lets the creamy filling settle and makes serving much easier. Sprinkle sliced green onions over the top if your family likes them, and add a little extra crumbled bacon if you have some left. Then bring the whole baking dish to the table while the cheese is still melted and the biscuits are warm.