Place rack in top third of oven. Preheat broiler to high.
Cut chicken into small pieces. Place on Sheet Pan; drizzle with oil and coat with Pina Colada Mix. Toss to evenly coat pieces. Broil, rotating pan and stirring often, until cooked through, about 8 min.
Meanwhile, peel and slice mango and avocado. Thinly slice cucumber into rounds and cut tomatoes into halves.
Arrange chicken, mango, avocado, cucumber, cherry tomatoes, and lettuce on a platter. Drizzle with dressing. Add toppings, if desired.
Per serving: Calories 370, Fat 19 g (Saturated 4 g, Trans 0 g), Cholesterol 85 mg, Sodium 125 mg, Carbohydrate 22 g (Fibre 4 g, Sugars 15 g), Protein 29 g.
Be sure to break up any lumps in the Pina Colada Mix before seasoning chicken.