Preheat oven to 350 F degrees. In a large skillet or a dutch oven melt the butter and saute onion for 3 minutes until transparent. Add bell pepper, celery and chicken. Cook for 5 min or until chicken is no longer pink. Add garlic, oregano, bay leaves and pepper.
Add marinara sauce, chicken stock or water, rice and stir. Cook until it comes to a boil. Add hot sauce, I used about 2 tbsp of hot sauce and it was nice and spicy for me, but if you don't like it so hot, use less. Cover the dutch oven and place in the oven and bake for about 30 to 45 minutes until rice is cooked.
In the meant time, clean the shrimp and season with cajun spice. Add the olive oil to a small skillet and heat the oil, then add the seasoned shrimp and cook about a minute per side, until it's pink and a bit crisp. You can cut the shrimp into small pieces or use it as whole.
Add shrimp and green onions to the jambalaya and stir.