In a 4-quart Dutch oven heat oil over medium heat. Add onion and cumin; cook about 5 minutes or until onion is tender, stirring frequently. Add broth, tomatoes, chicken, corn, and chile peppers. Bring to boiling; reduce heat. Simmer, covered, for 10 minutes.
To serve, divide crushed tortilla chips among soup bowls. Ladle soup into bowls over chips. Top with cilantro. If desired, sprinkle with cheese and serve with lime wedges.