Turn the Instant Pot to saute. Add the olive oil and butter to the Instant Pot. When melted and hot, add onions, garlic, celery, and carrots.. Saute, stirring often for 5-10 minutes (make sure not to brown them).
Add the tomato paste, salt, pepper. thyme, oregano and nutmeg. Saute for a minute or two, stirring until everything is incorporated.
Add ground beef, crushed tomatoes, milk and wine.Mix everything really well, making sure to completely break up the ground beef. Let simmer for about 7 minutes.
Close the lid. Set to Manual pressure setting for 35 minutes.
When finished, let the sauce natural release for about 5 minutes.
Remove the lid and stir well.