Add the elbow macaroni and water to the Instant Pot.
Close the lid and set the Instant Pot to high pressure for 4 minutes.
Once the cooking time is complete, perform a quick pressure release.
Open the lid and switch the Instant Pot to sauté mode.
Stir in the milk, shredded cheddar cheese, Parmesan cheese, garlic powder, onion powder, salt, and pepper.
Cook for a few minutes, stirring frequently, until the cheese is melted and the sauce is smooth.
Serve the mac and cheese while it's warm and creamy.