Preheat your oven to 350°F (175°C).

Cook the penne pasta according to package instructions. Once al dente, drain it well and set it aside to cool slightly.

Combine chicken, ranch dressing, buffalo sauce, and cooked pasta. In a large bowl, add half of the cheddar and mozzarella cheeses for that creamy goodness.

Season the mixture with salt and pepper. Give everything a good stir until all the ingredients are evenly coated and combined.

Transfer the delicious mixture to a greased baking dish. Spread it evenly for tasty flavor.

Top it off with the remaining cheeses and sprinkle the chopped green onions across the top.

Bake for 25-30 minutes or until the cheese is bubbly and golden brown.

Cool for a few minutes before serving to let the sauce thicken slightly.