Preheat the oven to 400 degrees F. Grease a 9 x 13-inch baking dish with 1 tablespoon of the oil and set aside.

Add the rice, chicken noodle soup mix, and water to a medium saucepan. Bring to a boil over medium-high heat.

Reduce the heat to low, cover, and simmer for 10 to 15 minutes, or until the liquid is absorbed and the rice is tender.

While the rice cooks, heat a large skillet over medium-high heat.

Add the sausage and cook for 6 to 8 minutes, breaking it into crumbles as it cooks, until browned and cooked through.

Transfer the cooked sausage to the prepared baking dish.

Add the remaining tablespoon of oil to the skillet if needed.

Add the onion, green bell pepper, and celery. Season with the salt, seasoning salt, oregano, and black pepper.

Cook for 5 to 7 minutes, stirring occasionally, until the vegetables are softened and the onions are translucent.

Transfer the vegetable mixture to the baking dish with the sausage.

Add the cooked rice mixture and stir until all ingredients are evenly combined.

Spread the mixture into an even layer and bake uncovered for 45 minutes to 1 hour, or until lightly browned on top and heated through.

Let the casserole rest for 5 minutes before serving.