Place the chicken breasts in a large saucepan and cover with the poaching liquid. Slowly bring the liquid to a simmer and poach gently for about 5 minutes. Cover the pan, remove from the heat and let cool slightly. Transfer the chicken and poaching liquid to a bowl. Cover and refrigerate overnight or until thoroughly chilled.
Line a serving plate with lettuce leaves. Drain and thinly slice the chicken. Arrange the slices on the lettuce. Dollop with orange mayonnaise and garnish with chives