Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper or a silicone baking mat. This prevents sticking and makes cleanup much easier once the meatballs are done.
In a large mixing bowl, combine the ground chicken, panko breadcrumbs, beaten egg, minced garlic, onion powder, smoked paprika, salt, and pepper. Use your hands or a spatula to gently mix the ingredients together until just combined. Be careful not to overmix, as this can make the meatballs tough.
Scoop about 1.5 tablespoons of the mixture and roll it into a ball, roughly the size of a golf ball. Place it on the prepared baking sheet. Repeat this process until all the mixture is used, leaving about an inch of space between each meatball. You should have about 16 to 20 meatballs.
Place the baking sheet in the oven and bake for 15 to 18 minutes. The meatballs should be cooked through and reach an internal temperature of 165°F (74°C). Once finished, remove them from the oven.
While the meatballs are still warm, place them in a clean bowl or back into a skillet over low heat. Pour the BBQ sauce over the meatballs and toss gently to coat every surface. Let them sit for a minute so the glaze thickens slightly and adheres to the chicken. Garnish with chopped green onions before serving.