Set the Instant Pot to saute mode and add 1 tablespoon of olive oil. Add the ground beef and ground pork, breaking the meat apart and cooking for 5 to 6 minutes until browned. Drain any excess grease, then remove the meat and set aside.
Add the remaining 1 tablespoon of olive oil to the pot along with the diced onion, carrots, and celery. Cook for 4 to 5 minutes until the vegetables are softened. Add the garlic and cook for 30 seconds.
Stir in the tomato paste and cook for 1 minute. Pour in the red wine and let it simmer for 2 minutes, scraping the bottom of the pot to deglaze.
Return the browned meat to the pot. Add the crushed tomatoes, milk, oregano, dried basil, bay leaf, salt, black pepper, and nutmeg. Stir everything together until well combined.
Lock the lid and set the valve to sealing. Pressure cook on high for 20 minutes.
When the cook time is complete, allow a natural pressure release for 10 minutes, then carefully switch the valve to venting. Remove the lid and discard the bay leaf.
Stir the bolognese well. Set to saute mode and let it simmer for 3 to 5 minutes uncovered to thicken if desired. Taste and adjust seasoning.
Serve the bolognese over cooked pappardelle or tagliatelle, topped with generous amounts of grated parmesan cheese and fresh basil.