Heat olive oil in a large skillet over medium high heat. Add ground beef, onion and garlic. Cook until beef has browned, about 3-5 minutes, making sure to crumble the beef as it cooks; drain excess fat.
Place ground beef mixture, crushed tomatoes, diced tomatoes and green chiles, oregano, basil and red pepper flakes into a slow cooker; season with salt and pepper, to taste. Stir until well combined.
Cover and cook on low heat for 7-8 hours or high heat for 3-4 hours.
Uncover and stir in tortellini; top with cheeses. Cover and cook on low heat for an additional 15-30 minutes, or until tender.
Serve immediately, garnished with parsley, if desired.