Preheat your oven to 390°F. If using a pre-made pizza base, follow the instructions on the package.
Place the flatbreads on a baking sheet lined with parchment paper.
In a bowl, mix the shredded chicken with 3 Tbsp of BBQ sauce. Let it sit for 5 minutes to soak in the flavor.
Spread a thin layer of BBQ sauce (about 1 Tbsp per flatbread) on each flatbread.
Evenly distribute the BBQ chicken over the flatbread.
Top with shredded cheese.
Add the sliced red onion and sweet pepper (if using).
Place the flatbreads in the oven and bake for 10-12 minutes, or until the cheese has melted and starts to lightly brown, and the edges of the flatbread become crispy.
Remove the flatbread from the oven and let it cool slightly.
Garnish with fresh cilantro or parsley.
Optionally, serve with sour cream or Greek yogurt and lime wedges.