Melt margarine in a medium nonstick skillet coated with cooking spray over medium-high heat. Add 1/4 cup onion; sauté until tender.
Combine broth and next 3 ingredients; stir until smooth. Add to onion mixture. Cook over medium heat, stirring constantly, until thickened. Add chicken, lemon juice, and salt. Cook over medium heat 6 minutes or until thoroughly heated, stirring occasionally.
Spoon chicken mixture over rice. Top evenly with banana, green onions, chutney, and peanuts.