Preheat oven to 375 degrees. Lightly grease a 13" x 9" baking dish with non stick cooking spray. Set aside.
In a large pot cook pasta according to package directions. Drain. Set aside.
While the pasta is cooking, heat a large skillet on medium high heat. Add the bacon and cook until crispy. Transfer bacon to a paper towel lined plate. Crumble bacon and set aside. Drain excess fat; reserving 3 Tablespoons of grease in the skillet.
In a Ziploc bag, add chicken, oil, and ranch mix. Shake and toss to coat evenly. Add to the skillet with the bacon grease and cook until no longer pink.
In a large bowl add pasta, alfredo sauce, chicken, ½ of the bacon, and ½ of the cheese. Pour into the casserole dish.
Top with remaining cheese and bacon.
Bake at 375 degrees for about 20 minutes until hot and bubbly.