Slice each chicken breast into four lenthways and add to a large bowl along with sweet chilli sauce, salt & pepper. Stir to combine and allow to marinate for 1-2 hours if possible.
Bring a large frying pan up to medium-high heat and add oil. Grill chicken on each side until browned and fully cooked through. Slice the chicken into 1" pieces and set aside. Add diced bacon to frying pan and cook until crispy. Set aside.
Meanwhile, roughly chop lettuce and add to a large bowl along with mango, avocado and tomatoes. Add chicken, bacon and feta.
For the dressing, add all ingredients to a small bowl and swirl around to combine. Pour over salad and toss thoroughly to evenly coat. Divide between four bowls and serve immediately.