Set the Instant Pot to "Sauté" and add the olive oil. Sprinkle in the flour and stir together until smooth. Cook, stirring constantly, until flour is medium brown in color, about 8 to 10 minutes.
Add the onion, bell pepper, celery, and garlic into the Instant Pot and sauté until softened, about 3 to 5 minutes.
Select “Keep Warm/Cancel” and add the stock, diced tomatoes, chicken, sausage, okra, Creole seasoning, oregano, thyme, basil, salt, pepper, cayenne, okra, Worcestershire sauce, and bay leaf to the Instant Pot and stir.
Close and lock the lid of the Instant Pot. Set the steam release to "Sealing", then select “Manual” and adjust the time to 8 minutes. Let cook until timer the beeps.
When finished, select “Keep Warm/Cancel” and then turn the valve to "Venting" for quick release. Carefully open the lid and stir in shrimp, salt, and black pepper. Select the "Sauté" and cook for 2-3 minutes, or until shrimp are cooked through. Turn off the Instapot and remove the bay leaf.
Serve in a bowl, topped with rice and garnished with fresh parsley, sliced green onion, and hot sauce, if desired.