Preheat oven to bake 375°F. Lightly brush each side of the corn tortillas with olive oil. Place on a baking sheet and bake in oven for about 5 minutes per side, until crispy. (if you bought tostada shells then omit this step)
While the shells bake, in a bowl mix the shredded chicken and BBQ sauce. Stir until well combined.
Once shells are ready, remove from oven and divide chicken evenly between the shells.
Top each one with shredded cheese.
Place back in oven on broil for about 5 minutes, or until the cheese has melted & started to turn golden brown, watching closely so not to burn.
Remove from oven and top with tomatoes, cilantro, diced red onion, cilantro and a drizzle of BBQ sauce.
