Add the remaining 1 tablespoon of butter to the pot with the sausage and drippings. When the butter melts, add the celery, bell pepper, and onion. Cook, stirring, until the vegetables start to soften, about 5 minutes. Add the garlic and cook, stirring constantly, until fragrant, about 1-2 minutes. Reduce the heat to medium. Stir in the salt, thyme, oregano, paprika, cayenne pepper, and black pepper. Cook and stir for 1 minute. Add the rice and tomato paste. Cook, stirring constantly, until the rice is toasted, about 2-3 minutes. Add the broth and tomatoes, using your hands or a wooden spoon to break up the tomatoes as you stir them into the pot. With the same wooden spoon, scrape up any browned bits from the bottom of the pot. Increase the heat to high, and bring the liquid to a boil. Stir in the chicken and half of the green onions. Remove from the heat.