Heat oil in large dutch oven over medium heat. When hot, add onion and garlic, cooking until softened.
Stir in beef, salt and pepper cooking until browned. Add broth, taco seasoning, tomatoes and corn. Increase heat to medium high and stir in uncooked tortellini. Cook for 8-10 minutes or until pasta is al dente. Immediately remove soup from heat when pasta is cooked. Stir in fresh cilantro and serve.