Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Place the naan or flatbreads on the prepared baking sheet.
Lightly brush each flatbread with olive oil.
Spread the basil pesto evenly over the surface, reaching close to the edges.
Top with shredded chicken, mozzarella cheese, cherry tomatoes, and sliced red onion.
Season lightly with salt and black pepper.
Bake the Pesto Chicken Flatbread for 10–12 minutes, or until the cheese is melted and bubbly and the edges are golden brown.
Remove from the oven and garnish with fresh basil leaves.
Add red pepper flakes or a drizzle of balsamic glaze if desired.
Slice and serve warm.