Preheat oven to 190°C / 375°F.
Line a baking sheet with parchment paper.
In a big mixing bowl, add chicken mince, cornstarch, cold water, garlic powder, salt and black pepper. Mix until thoroughly combined.
Place panko crumbs in a big shallow bowl.
Using two spoons or wet hands, shape 1 tbsp of chicken mixture into a nugget. Place nugget in the bowl with panko crumbs, roll and press down gently to coat the entire nugget in panko crumbs evenly. Transfer to lined baking sheet.
Repeat step 5 with remaining chicken mixture.
Spray nuggets lightly with cooking spray.
Bake nuggets for 15 minutes or until cooked through, flipping them halfway through baking.
Remove nuggets and let cool slightly before serving. Enjoy with your favourite sauces!