Place chicken and marinade in a glass bowl or dish, cover and allow to marinate for 30 minutes in the refrigerator. Pan-fry chicken over medium-high heat until browned on both sides and cooked completely through.
Preheat oven to 400 degrees F. Place flatbreads on large baking sheet or pizza sheet.
Dividing evenly between flatbreads, top with cheese, chicken, mango and tomatoes.
Bake Flatbread for 12 minutes or until cheese is melted through.
Remove from oven and top with avocado.
Drizzle the flatbread with chili sauce.
Slice and serve immediately.