Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius) and lightly grease a 9x13 inch baking dish.
In a large mixing bowl, combine the softened cream cheese, sour cream, dry ranch seasoning, milk, and minced garlic, whisking until the mixture is smooth.
Fold the shredded chicken and half of the crumbled bacon into the cream cheese mixture.
Spread a thin layer of the chicken mixture onto the bottom of the prepared baking dish.
Place three lasagna noodles side-by-side over the sauce layer.
Spread one-third of the remaining chicken mixture over the noodles, then sprinkle with one-third of the cheddar and mozzarella cheeses.
Repeat the layers of noodles, chicken mixture, and cheese twice more, finishing with a final layer of cheese and the remaining crumbled bacon.
Cover the baking dish with aluminum foil and bake for 20 minutes.
Remove the foil and continue baking for 15 to 20 minutes, or until the cheese is bubbling and starting to brown.
Remove from the oven and garnish with sliced green onions.
Let the lasagna rest for 10 minutes before slicing to allow the layers to set.