Preheat the oven to 350°F. Spray a 9X13 inch baking dish with nonstick cooking spray.
Cook the pasta (1 pound) in well-salted water, according to package instructions. Drain and dry pot.
Add alfredo sauce (2 (15 ounces)), sour cream (1 cup), milk (1 cup), dry ranch dressing mix (1 envelope), dill (▢1 teaspoon), 1 cup Mozzarella, 1 cup cheddar, and bacon (6 slices) to the pot dried pasta pot and stir to combine. Add pasta and chicken (3-4 cups) and stir until evenly coated.
Pour mixture into prepared baking dish. Sprinkle top evenly with the remaining 1 cup of Mozzarella and 1 cup of cheddar. Bake in preheated oven until heat through and bubbly, about 25-30 minutes. Serve.