Preheat oven to 350 degrees F (180 degrees C).
Add 1 tablespoon of olive oil to a large stockpot or Dutch oven set over medium-high heat. Add the sliced sausage and cook for approximately 1 minute per side. Remove to a clean plate and set aside. Note: If you are using raw sausage (i.e., non-smoked sausage), cook the sausage whole first. Once it’s cooked, remove it from the pan, let it rest, and then slice it before adding it to the pot.
Add the chicken to a large bowl and season with salt, pepper, and about 1 tablespoon of Cajun seasoning. Set the same pot used to sear the sausage over medium-high heat. Add 1 more tablespoon of olive oil and add the chicken. Cook, stirring occasionally, for 6-8 minutes or until it registers 165°F (75°C) with a digital meat thermometer. Transfer the chicken to a clean plate and set aside.
Add the last tablespoon of olive oil to the pot and set it over medium-low heat. Add the finely chopped onions, bell pepper, and celery, mixing well to combine. Cook for 8-10 minutes, stirring frequently, until softened.
Add the minced garlic, Cajun seasoning, salt, pepper, cayenne pepper (optional), Italian season, and red pepper flakes (optional). Mix well to combine and continue to cook for an additional minute.
Mix in the crushed tomatoes, Worcestershire sauce, white rice, and low-sodium chicken broth with the softened veggies. Mix well to combine. Bring to a boil, then immediately reduce the heat to low and cover with a tight-fitting lid.
Cook for approximately 25-35 minutes or until the rice is nearly cooked, gently stirring every 7-8 minutes to prevent the rice from burning and sticking to the bottom of the pot. To cook the rice in the oven, transfer the covered pot to the preheated oven and bake for approximately 25-35 minutes or until the rice is nearly cooked. As the rice cooks, melt 2 tablespoons of butter in a large skillet set over medium-high heat and cook the shrimp for 2 minutes on each side.Note: Cooking the shrimp in a separate skillet is optional. You can add the uncooked shrimp with the okra, chicken, and sausage (see next step). The hot rice will cook the raw shrimp. When the rice is nearly finished cooking, stir in the shrimp and the sliced okra, and return the chicken and sausage back to the pot. Gently mix to combine with the rice. Continue to cook on low, stirring as needed, until the shrimp is cooked, approximately 5-8 minutes.
Remove from heat. Serve warm garnished with chopped parsley and green onion if desired. Refrigerate leftovers in a sealed container for up to 4 days. Enjoy!