Cook and stir onion and garlic in 2 TBSP oil in 4 qt. Dutch oven until onion is tender. Stir in broth, bell pepper, ground red chiles, basil, salt, pepper and tomato puree. Heat to a boiling. Reduce heat and simmer, uncovered for 30 minutes. Divide tortilla chips, chicken avocado slices and cheese among 6 soup bowls. Pour broth over. 6 (1 1/2 cup) servings.