Add 1 tablespoon of oil to the Instant Pot insert and brown the chicken over medium-high heat using the sauté function. Remove and set aside.
Using the sauté function again, heat the oil and flour over medium heat.
Cook, whisking constantly, until the mixture turns a caramel brown color. This will take about 10-12 minutes. (Learn more about how to make a roux).
Add the diced green pepper, onion and celery and cook for 2 minutes, until vegetables start to soften.
Stir in the diced tomatoes until a paste-like mixture forms.
SLOWLY pour in the chicken stock, whisking constantly to avoid clumping.
Stir in all of the seasonings.
Add the okra, chicken and sausage.
Lock the lid in place, turn the valve to seal and set the Instant Pot to pressure cook on high for 15 minutes.
Let the pressure release naturally for 10 minutes, then manually release any remaining pressure.
Taste and adjust the salt, if needed. Serve over white rice garnished with sliced green onions.