BBQ Chicken Tostadas

to stada shells (or 8 corn tortillas, brushed lightly with olive oil and baked for 3-5 minutes per side, until crispy)

cooked and shredded chicken

your favorite barbecue sauce (divided)

shredded cheese (Mary uses mozzarella in the cookbook, but I have also used cheddar, Monterey Jack, or a blend)

green onions (very thinly sliced (optional))