In a large pot, heat the oil and then add the onions and garlic.
Cook, stirring occasionally, until onion is tender and translucent.
Stir in sweet potatoes, broth, cumin, oregano, chili powder, and red pepper.
Bring to a boil and then reduce heat to low and simmer, covered, for about 20 minutes or until sweet potatoes are tender.
Using about 2 cups (more if you prefer a creamier soup), puree the soup in a food processor or blender until smooth and then return the mixture to the pot.
Add the diced tomatoes, corn, green chilies, and cilantro to the soup and continue to cook over medium heat until the soup is heated thoroughly.
To serve, ladle soup into individual bowls and sprinkle with tortilla chips.