Place the chicken breasts in a large pot with water and bring it to a boil set over medium-high heat. Boil the chicken until a thermometer inserted in the middle of a chicken breast reads 165°F or higher. Test to see if the chicken is ready by pushing a fork into it and see if it is easily shreddable.
Remove the chicken from the boiling water and place on a cutting board to cool slightly. When the chicken is cool enough to handle, shred by hand with two forks or place the chicken in the bowl of a stand mixer. Using the paddle attachment, turn the mixer on to low or medium speed to shred the chicken.
Preheat the oven to 350°F and prepare a large casserole dish with baking spray.
In a microwave safe bowl, place the cream cheese in the microwave and melt slightly until softened and easy to mix.
Stir in the ranch seasoning packet and buffalo sauce. Mix until fully combined.
In the prepared casserole dish, mix together the shredded chicken and the cream cheese mixture.
Top with the cheddar cheese and place in the oven. Bake for about 20 minutes, or until the cheese is melted.
Serve warm with your favorite crackers and vegetables.