Bring a pot of water to boil over high heat, add in the chicken and season it lightly. Allow it to boil for a couple of minutes then turn off the heat, and allow it to sit covered for about 25 minutes. Remove from the pot and allow to cool until it can be handled easily. Now, using two forks, shred the chicken.
Preheat your oven to 350°F (or 180°C). Spray your 9x9 inch baking pan with non-stick cooking spray.
Get a large skillet over medium-low heat, and add in cream cheese, hot sauce, ranch dressing, black pepper, garlic powder, and salt. Whisk together until the cheese is melted and everything is well combined, then from the heat.
Add the shredded chicken, one cup of mozzarella, one cup of cheddar, and green onions to the skillet and mix well until combined.
Transfer the mixture to your sprayed baking pan, and top off with the remaining mozzarella and cheddar cheese.
Bake in the preheated oven for about 20-30 minutes, or until the cheese has melted and the sides are bubbling. Now, set your oven to broil for about 5 minutes, or until the top is golden brown.
Viola! Your delicious Buffalo Chicken Dip is ready. Serve with tortilla chips, crackers, pita bread, or any other sides you enjoy.