BBQ Chicken Sandwiches with Jalapeño Avocado Spread

boneless, skinless chicken breasts

low-sugar BBQ sauce

whole wheat buns

avocado, pitted

small jalapeño, seeded and diced (keep the seeds for more heat)

juice of ½ a lime (about 1 tablespoon)

chili powder

lettuce

tomato

thin sliced provolone cheese