In a large pot over medium heat, saute the garlic and onion in the butter or margarine for 5 minutes.
Add flour and stir well, cooking for 1 minute more.
Add the broth and half-and-half. Bring to a boil and reduce heat to low.
Add the soup, salsa, corn, chicken, cumin, fajita seasoning and 2 tablespoons cilantro. Stir and continue to heat for 15 minutes. Crumble tortilla chips into individual bowls, add 1/2 ounce shredded cheese to each bowl and ladle in soup. Top each bowl with more crumbled chips, remaining 1/2 ounce cheese and remaining 1 tablespoon cilantro, and serve.