Heat olive oil in a large skillet over medium heat.
Add the chicken sausage and cook until browned on both sides.
Stir in chopped onion and minced garlic; sauté until softened.
Add rice, chicken broth, tomato sauce, oregano, salt, and pepper.
Bring to a simmer, cover, and cook for 18–20 minutes until rice is tender.
Fluff with a fork, top with Parmesan and parsley, and serve warm.