In large saucepan, melt margarine over medium-high heat. Add onion and bell pepper; cook and stir until crisp-tender. Stir in chicken broth, chicken, tomatoes, beans, corn, salt, pepper and crushed red pepper flakes. Bring to a boil. Reduce heat to low; simmer 15 minutes. Add okra; simmer an additional 5 minutes or until okra is tender.