In 3-quart saucepan or 4-quart Dutch oven, heat oil over medium-high heat. Add celery, bell pepper, onion and garlic; cook and stir 3 minutes.
Stir in all remaining ingredients. Heat to boiling. Reduce heat; cover and simmer 30 to 40 minutes, stirring occasionally, until vegetables are tender and flavors are blended. If desired, top individual servings with crushed tortilla chips and sliced green onions.