Finely dice your onion, carrots, and celery.
Mince your proscuitto, mortadella, and ground pork.
Add the olive oil to the Instant Pot and select saute high. Once hot, add the onions, carrots, and celery. Caramelize, stirring occasionally, about 5 minutes.
Add the meats, parmigiano rind, and just enough stock to barely cover (about 1/2 qt) to the pot. Cover and set to high pressure for 2 hours and 15 minutes.
When the time is up, quick release, then remove the parmigiano rind.
Set the heat to saute high again, and cook, stirring, until the sauce is reduced to your liking, about 5-10 minutes. Stir in the cheese and enjoy.