Combine the water, pasta, butter, minced garlic, garlic powder and cayenne in the Instant Pot. Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 4 minutes.
When the time is up, quick-release the pressure. If pasta is not completely cooked, use the SAUTE function and cook, stirring occasionally, for another 2-3 minutes.
Add evaporated milk and cheeses, one at a time, stirring between each until the mixture becomes thick and creamy.
Salt to taste.