Remove chicken from the bone and chop into bite-size pieces. Place in a large bowl. NOTE: You can do this step the day before, then store in an airtight container and keep refrigerated.
Peel and dice mango. Add to chopped chicken.
Coarsely chop cilantro. Slice the jalapeño pepper in half lengthwise and remove seeds and pith, then mine. Add both to chicken mixture. NOTE: We usually start with half of the pepper and add more at the end if desired.
Thinly slice scallions (both green and white parts). Add to chicken mixture and toss.
Juice one lime directly into the mixture, then add mayonnaise, salt, pepper, and red pepper flakes. Toss to combine well. Taste then add more mayonnaise, jalapeño, and juice of the other lime, if desired. Adjust other seasonings, to taste.
Toast pecans, or use raw. Chop and sprinkle on top of salad right before serving.