Coat grill rack with nonstick cooking spray. Preheat grill to medium, 300 F degrees to 350 F degrees.

Sprinkle cut sides of banana halves with sugar. Place bananas on grill, sugar side up. Grill covered for 2 minutes. Turn bananas with sugar side down and grill for another 2 to 3 minutes or until slightly softened and grill marks form. Remove from grill; let cool slightly.

Cut each banana half in half. Place 2 banana slices and 1 scoop of ice cream in each of 4 dessert bowls. Drizzle with chocolate sauce, top with peanuts, and serve.