While the pasta is cooking: In a bowl, use a hand mixer to beat the cream cheese until smooth.
Add in the evaporated milk, ¼ of a cup at a time, mixing between each addition. Mixing in the milk slowly will help your mixture to stay smooth and not have small chunks of cream cheese.
Add the ranch dressing and buffalo sauce. Mix well.
Add the chicken and 1 ½ cups cheese. Stir to combine.
Mix in the drained pasta until it is coated.
Spray a 9x13 baking pan with cooking spray.
Add noodle mixture to the casserole. Spread it out evenly.
Top with the remaining cheese.
Bake for 25-30 minutes or until it is bubbly and heated through. I do 25 minutes, then 3 minutes under the broiler on low to crisp up the top.
Drizzle ranch dressing over the top of the casserole.
Sprinkle with sliced green onions or bleu cheese crumbles.
Notes
The calories shown are based on the recipe serving 10, with 1 serving being 1/10 of the casserole. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**