Preheat the air fryer to 400°F (200°C).
In a small bowl, whisk together the egg and water to create an egg wash.
In a separate shallow dish, combine the panko breadcrumbs, almond flour, lemon zest, black pepper, salt, and garlic powder.
Dip each chicken cube into the egg wash, then coat thoroughly in the breadcrumb mixture, pressing firmly to ensure adherence.
Arrange the coated chicken pieces in a single layer in the air fryer basket, avoiding overcrowding.
Lightly spray the chicken nuggets with olive oil spray.
Cook for 6 minutes, flip the nuggets, spray lightly again, and cook for an additional 4 to 6 minutes until golden brown and the internal temperature reaches 165°F (74°C).