Turn the instant pot to saute mode (higand add the olive oil.
In a large bowl, add the cubed chicken and coat with the ranch mix and garlic powder.
Once the oil is hot, add the chicken and saute until golden on all sides. Turn the pot off.
Remove the chicken to a plate. Pour in about 1/4 cup of the water and use a wooden spoon to deglaze the bottom of the pot.
Add the macaroni, remaining water, HALF of the buffalo sauce, butter, and salt and pepper to taste. Return the chicken to the pot.
Place the lid on the pot and set the valve to sealing.
Cook on manual, high pressure for 5 minutes. Then, carefully do a quick release.
Add the milk, cream cheese and remaining buffalo sauce to the pot and stir well. Add the cheese in 3-4 handfuls, stirring in between each addition, until smooth and creamy.