1/2 lb smoked sausage, sliced into 1/4-in.-thick rounds
1 lb boneless, skinless chicken thighs cut into 1-in. pieces
2-1/2 t Cajun seasoning divided
1 chopped medium yellow onion
1 chopped large celery stalk
1 chopped small green bell pepper
1 chopped small red bell pepper
2 t minced garlic
2 C chicken broth
1 14.5-oz can diced tomatoes
2 C uncooked long-grain rice
2 bay leaves
3/4 t thyme
1 pound medium peeled, deveined raw shrimp
1/4 t kosher salt
1/4 t black pepper
Select SAUTÉ setting on a programmable pressure multicooker (such as Instant Pot). (Time, instructions, and settings may vary according to cooker brand or model.) Select HIGH temperature setting, and allow to preheat 5 to 8 minutes. Add oil, and stir in smoked sausage. Cook sausage, stirring often, until browned, about 5 minutes. Remove with a slotted spoon, and set aside.
Add chicken to cooker, and sprinkle with 1/2 teaspoon of the Cajun seasoning. Cook, stirring often, until browned, about 5 minutes. Remove chicken with a slotted spoon, and set aside.
Add onion, celery, green bell pepper, and red bell pepper to cooker, and cook, stirring occasionally, until vegetables begin to soften, about 4 minutes.
Add garlic, and cook, stirring constantly, 1 minute.
Add broth, diced tomatoes, rice, bay leaves, thyme, sausage, chicken, and remaining 2 teaspoons Cajun seasoning, stirring well to combine ingredients.
Cover cooker with lid, and lock in place. Turn steam release handle to SEALING position. Select MANUAL/PRESSURE COOK setting. Select HIGH pressure for 7 minutes.
Toss shrimp with salt and black pepper in a medium bowl.
When cooking has stopped, carefully turn steam release handle to VENTING position, and let steam fully escape (float valve will drop). Remove lid from cooker, and stir in shrimp. Return lid to cooker, and let stand until shrimp are pink and have cooked through, 8 to 10 minutes.