Melt butter in a Dutch oven over medium heat. Add celery and green bell pepper; cook, stirring occasionally, 5 minutes or until tender.
Combine flour and 2 tablespoons chicken broth; stir with a whisk until smooth. Add flour mixture to remaining broth; stir well. Add broth mixture, corn, and next 6 ingredients to pan; stir well. Bring to a boil; cover, reduce heat, and simmer 10 minutes, stirring occasionally. Ladle chowder into bowls. Sprinkle each serving evenly with parsley.