Remove avocado flesh from shell and mash with a fork or potato masher. Mix in remaining ingredients and set aside.
For the burgers:
Coat grill or grill pan with nonstick cooking spray. Cook Chicken Patties according to package directions, about 9-11 minutes, turning once. About 1 minute before removing from grill, brush patties with BBQ sauce (about 1 Tbsp. each).
Layer hamburger buns with lettuce, Chicken Patties, pineapple guacamole and tomato.