Generously coat the inside of the Crock Pot with cooking spray.
Lay the chicken breasts inside the Crock Pot.
Pour in the chicken broth, followed by the Buffalo sauce and ranch dressing, ensuring the chicken is well-coated.
Scatter the cubed cream cheese over the chicken.
Secure the lid and set the Crock Pot to cook on HIGH for 2 hours.
After 2 hours, remove the chicken from the Crock Pot using tongs and place it on a cutting board.
Add the uncooked penne noodles to the Crock Pot, stirring thoroughly to combine.
Replace the lid and allow the pasta to cook for an additional 30 minutes.
Meanwhile, chop the chicken breasts into bite-sized pieces.
Once the pasta has cooked for 30 minutes, remove the lid and stir the mixture.
Return the chopped chicken to the Crock Pot, stirring well to incorporate.
Add the shredded mozzarella and cheddar cheese blend, stirring until evenly mixed.
Cover and cook for another 10 minutes to heat the chicken through and melt the cheese.
Stir in 1/2 cup of the chopped green onions, mixing them well into the pasta.
Garnish with the remaining 2 tablespoons of green onions and serve immediately.