Cook plantain slices in boiling water 15 minutes or until very tender. Drain, place in a large bowl. Mash plantain with a fork until smooth; cool 5 minutes. Add green onions and next 7 ingredients (through chicken). Divide mixture into 6 equal portions, shaping each into 1/2 inch thick patty.
Grill 4 minutes each side or until a thermometer registers 165 degrees. Remove from grill, let stand 5 minutes.