Preheat oven to 350°F. Cook and shred the chicken if it isn't already prepared.
In a small saucepan over medium heat, combine the cream cheese and ranch dressing. Cook, stirring frequently, until the cream cheese is fully melted and the mixture is smooth. Add 1 cup of mozzarella cheese and continue stirring until it is fully melted and combined.
In a large mixing bowl, toss the shredded chicken with the buffalo sauce until it is evenly coated. Spread the chicken mixture into an even layer in a 9x13-inch baking dish. Pour the cream cheese mixture over the chicken and use a spatula to spread it evenly to the edges of the dish. Sprinkle the remaining mozzarella and cheddar cheese evenly over the top.
Bake for 20-25 minutes, or until the dip is hot and bubbling and the cheese is melted and lightly golden. Garnish with chives if desired and serve warm with tortilla chips, crackers, and fresh vegetables.
Ranch Dressing: Hidden Valley ranch, homemade ranch, or blue cheese dressing all work well for this recipe.
Cheese: Shred your own cheese, don't use pre-shredded cheese, or the dip will turn grainy. Any kind of cheese that melts well can be used for this dip. Some other options are Provolone, Havarti, or Monterey Jack.
Hot Sauce: The classic hot sauce is Frank's Red Hot. But you can use any type that you like.
Cream Cheese: Regular or light cream cheese both work.
To make this in the slow cooker, combine all of the ingredients (excluding the cheese for topping) in the slow cooker. Cook on low, stirring regularly for 2-3 hours until completely melted and smooth. Add the cheese for topping, and let it melt before serving straight out of the slow cooker.
Easily make this dip spicier by adding more hot sauce, red chili flakes or top with chili crunch oil. To make it a milder dip, use more ranch dressing or less hot sauce.
Overbaking the dip can result in it turning oily. Remove it from the oven as soon as it is hot and bubbly.
Store leftovers in an airtight container and keep it in the fridge for up to 3 days.
To make this ahead of time, prepare it right up to step 4, and instead of baking, wrap it tightly with plastic wrap and store it in the fridge for up to 2 days. Bake and serve fresh.