In a medium saucepan, sauté onion and garlic in oil over medium-high heat 5 to 7 minutes or until onion softens and begins to brown. Add beans, corn, tomatoes, water and taco seasoning mix. Bring to a boil; reduce heat to low and simmer 15 minutes, stirring occasionally.
Combine chiles in sauce and vinegar in a blender; process until pureed. Stir chile mixture and cilantro into chili, adding more taco seasoning mix if a spicier chili is preferred; heat through. Divide among 4 soup bowls; top with dollops of sour cream. Garnish with salsa and a sprig of cilantro, if desired.