Turn the Instant Pot on the Saute function. Add 1 tbsp of the olive oil to the pot. Then add the chicken sausage. Cook for 2-3 minutes.
Remove the chicken sausage from the pot. Add the butter and remaining tbsp of olive oil to the pot. While it melts add the flour in 3 phases. Add the first phase and whisk. Add the second phase, and so on.
Continue to whisk until the roux turns peanut butter brown. It should turn brown within a few minutes of whisking. Press Keep Warm/Cancel on the Instant Pot so the roux does not burn.
Add the green peppers, celery, and onions. Stir and cook for 2-3 minutes until the veggie are soft.
Add all of the seasonings, garlic, and worcestershire sauce to the pot.
Next add the chicken broth, diced tomatoes, okra, and Better Than Bouillon. Stir. Add the water.
Place the chicken breasts in the pot and return the chicken sausage to the pot.
Close the pot and seal. Cook on Manual High-Pressure Cooking for 15 minutes. When complete, allow the steam to release naturally for 10 minutes instead of quick release.
Remove the chicken from the pot and shred.
Place the Instant Pot on the Saute function. Add the raw shrimp and shredded chicken to the pot.
Cook for a few minutes until the shrimp turns bright pink.
Serve the gumbo alongside the cooked white rice.