In a medium pot or saucepan, bring 6 cups of salted water to a boil. While waiting for the water to boil, prepare a large bowl with ice water. Add broccoli florets to the boiling water and cook until tender, 1 to 2 minutes.
Arrange lettuce leaves on a large platter. Pour chilli sauce into a small bowl place on platter with leaves.Mix chicken, onions, soy sauce, and corn-starch in a medium bowl marinate 10 minutes at room temperature, stirring occasionally.