Using the sauté setting on your Instant Pot, add oil and sausage. Cook for about 5 minutes until the fat is rendered and the edges are crisp.
In an oven-safe glass bowl, whisk together the grits, milk, and chicken stock. Set aside.
Add onions to the pot and sauté for about 3 minutes until softened and translucent. Add garlic and continue cooking for one minute.
Add wine and cook for about 5 minutes, scraping up any brown bits from the bottom of the pot. Add tomatoes, thyme, and creole seasoning, and mix well.
Place a 3-inch trivet in the Instant Pot, then place the bowl of grits on top of the trivet. Lock the lid and cook on high pressure for 10 minutes. Allow the pressure to release naturally (about 10 minutes).
Carefully remove the bowl from the Instant Pot. Add butter to the grits and whisk well to break up any clumps. Cover until ready to serve.
Switch the Instant Pot back to the sauté setting. Add parsley and green onions and mix well. Bring to a boil.
Add shrimp and cook for about 5 minutes, stirring every 30 seconds, until the shrimp turn pink.
Add the cream and mix well before the shrimp are fully cooked. Switch the pot to the warm setting.