Cook the shells per the instructions on the package for aldente.
Butter a 9x13-inch baking dish. Set aside until needed.
Add the softened cream cheese, ranch seasoning mix, cream of chicken soup, sour cream, and half and half to a large bowl. Whisk until smooth and creamy.
Add the cooked shredded chicken, shredded cheddar cheese, crumbled bacon, and cooked pasta to a large bowl. Mix until well combined.Save some of the bacon to garnish the casserole.
Pour the mixture into the prepared baking dish and spread evenly using a rubber spatula.
Place the casserole on the center rack of the preheated oven and bake for 20 - 25 minutes or until bubbly.
Add the crushed Ritz crackers and melted butter to a medium bowl and mix to combine.
Sprinkle the buttered Ritz crackers over the top of the casserole and return it to the oven. Bake for an additional 10 minutes until the crackers begin to brown.
Remove from the oven and let it cool for 7-10 minutes before serving.
Garnish with sliced green onions and chopped bacon.