Preheat the oven to 400°F (200°C) and line a baking sheet with parchment or lightly oil it.
In a small saucepan over medium heat, melt the butter.
Add the minced garlic to the butter and cook about 30 seconds until fragrant and lightly golden.
Sprinkle in the flour and cook, whisking constantly, for 30 seconds to 1 minute until lightly browned.
Slowly whisk in the milk and continue whisking constantly until the sauce thickens and becomes bubbly, about 5 minutes.
Remove the sauce from heat and stir in the shredded Parmesan, a pinch of red pepper flakes, and salt and pepper to taste.
Place the naan loaves on the prepared baking sheet and divide the Alfredo sauce between them, spreading evenly.
Top each naan with the cooked diced chicken, shredded mozzarella, and halved cherry tomatoes.
Bake for 12 to 14 minutes, until the naan edges are toasted and the cheese is melted and bubbly.
Remove from the oven, top with fresh basil if using, slice, and serve.