Spray the inside of the Crock Pot generously with cooking spray. Place the boneless, skinless chicken breasts into the bottom of the pot.
Pour the chicken broth, Buffalo sauce, and ranch dressing evenly over the chicken breasts.
Add the cubed cream cheese on top of the liquids and chicken.
Place the lid on the pot and set it to cook on HIGH for 2 hours.
After 2 hours, use tongs to remove the chicken and transfer it to a cutting board.
Add the uncooked penne noodles to the pot and give it a good stir.
Return the lid and cook for an additional 30 minutes.
While the pasta cooks, chop the chicken into bite-sized pieces.
After 30 minutes, stir the mixture well. Add the chopped chicken along with the shredded mozzarella and cheddar cheese.
Cook for an additional 10 minutes to allow the cheese to melt.
Add the chopped green onions and stir to combine.
Garnish with any remaining green onions and serve warm.