In a 1.5 quart casserole, whisk together Grits Mixture ingredients. Set aside.
Season shrimp with Old Bay and set aside.
Add diced bacon to the Instant Pot. Using the display panel select the SAUTE function. Cook and stir until crisp. Using a slotted spoon, remove bacon to a paper towel lined plate.
Add bell pepper and onion to the pot and cook until soft, 2-3 minutes. Add garlic and cook for 1-2 minutes more.
Add broth, wine and lemon juice to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Stir in tomatoes, salt and pepper, then put steam rack into the pot (optional: to save clean-up I often use a tall steam rack or riser to keep the bottom of the grits out of the sauce)
Carefully lower the casserole onto the steam rack, then 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 10 minutes.
When the time is up, let the pressure naturally release.
Once the steam is fully released, quickly remove the casserole and steam rack from the pot and set aside. Stir the shrimp into the pot, then close the lid to allow shrimp to cook in the residual heat.
Meanwhile, add 1 tbsp butter to the grits and fluff with a fork to achieve desired consistency.
When shrimp are no longer opaque (5-10 minutes depending on shrimp size), stir heavy cream into the pot, returning to SAUTE mode as needed to heat through.
Add hot sauce to taste. Serve shrimp and sauce over grits topped with green onions and crumbled bacon.