Preheat an oven to 400ºF and remove the tops, seeds, and membranes from the bell peppers. Place the peppers in a 13x8 baking dish. Set aside.
Add the chicken stock, buffalo sauce, and cream cheese to a nonstick skillet over medium-low heat. Cook for a few minutes until smooth before adding the ranch seasoning.
Once the sauce is evenly mixed, turn off the heat and add the shredded chicken, folding everything together.
Fill the peppers with the chicken mixture and loosely cover with foil, keeping it off the top of the peppers. Bake for 20 minutes before removing the foil and adding the shredded cheese.
Bake an additional 15-20 minutes until the peppers are fork tender. You can use your oven's broil function for the last 2-3 minutes for extra bubbly cheese, if desired.