Preheat oven to 425 degrees F (220 degrees C). Spray a 9 x 13-inch baking dish with cooking spray.
In the prepared baking dish (or in a separate bowl), whisk together Alfredo sauce, chicken broth and Ranch seasoning packet until completely combined.
Stir in the uncooked pasta, chicken, bacon, and garlic.
Cover the dish tightly with foil. Bake for 35 minutes.
Uncover; stir. At this point, the pasta should be al dente (firm but just about finished cooking). There will still be plenty of liquid in the dish, but don’t worry – this will thicken as the dish continues to bake and cool.
If the pasta is still too hard after 35 minutes, just cover the dish and return to the oven until pasta is al dente. Then move on to the next step.
Sprinkle mozzarella over top. Bake, uncovered, for 5-10 more minutes (or until cheese is melted and pasta is tender). Allow to rest for about 5-10 minutes before serving (the sauce will continue to thicken as it cools).
Garnish with grated Parmesan and fresh parsley, if desired.