Place the elbow macaroni, ground mustard, onion powder, garlic powder, salt, black pepper, butter, hot sauce, and water in a 6-quart Instant Pot. Close the lid, making sure the pressure valve is in the “sealing” position.
Set the Instant Pot to “manual” and cook for 4 minutes.
As soon as the Instant Pot beeps, carefully release the pressure from the pot. Remove the lid and stir the noodles.
Then stir in the heavy cream, cheddar cheese, and mozzarella cheese.
Stir until melted, then serve immediately.