Combine the soy sauce and honey in a small bowl; set aside.
Heat the oil in a large skillet over medium-high heat.
Season the chicken with 1/2 teaspoon pepper and cook, stirring occasionally, until it begins to brown, about 3 minutes.
Lower heat to medium and stir in the garlic and ginger. Add the scallions and cook for 1 minute. Stir in the water chestnuts and half the soy sauce mixture and continue to cook until the chicken is cooked through, about 4 minutes. Remove from heat and sprinkle with the cashews.
Divide the lettuce leaves among individual plates and spoon the chicken over the top. Serve with the remaining soy sauce mixture for drizzling.
Substitution: In place of the chicken, try steak, pork, or shrimp in this zesty update of the Chinese-restaurant classic.