Brown the beef: Heat olive oil in a large skillet over medium heat. Add diced onion and sauté until softened, about 3 minutes. Add ground beef, breaking it up with a spoon, and cook until browned. Drain excess grease if needed.
Season the beef: Stir in garlic powder, cumin, chili powder, salt, and pepper. Mix until well combined and fragrant, about 1 minute.
Add sauce and tortellini: Pour in the enchilada sauce and beef broth. Stir in the cheese tortellini.
Simmer: Bring the mixture to a light simmer. Cover and cook for 5–7 minutes, or until tortellini is tender and heated through.
Add cheese: Sprinkle shredded cheddar and Monterey Jack over the skillet. Cover again for 2–3 minutes, or until cheese is fully melted.
Serve: Garnish with cilantro, sour cream, or jalapeños if desired. Serve hot!