Add the cubed chicken breasts, sliced andouille sausage, diced tomatoes, chopped onion, celery, red bell pepper, tomato paste, chicken broth, thyme, oregano, and Cajun seasoning to a large pot. Stir well to combine.
Place the pot over medium heat and bring the mixture to a gentle simmer. Cover and cook until the vegetables begin to soften and the chicken is cooking through, stirring occasionally.
Stir in the uncooked long-grain rice, making sure it is covered by the liquid. Cover and continue simmering until the rice is tender, stirring occasionally to prevent sticking. Add a little extra hot broth if the mixture becomes too dry.
Once the rice is nearly tender, add the peeled and deveined shrimp. Gently stir and continue cooking until the shrimp are pink, opaque, and fully cooked, and the chicken reaches an internal temperature of 165°F (74°C).
Give the jambalaya a final gentle stir to distribute the chicken, sausage, shrimp, and rice evenly. Spoon into serving bowls and serve warm.
