Preheat the oven to 375 degrees F. Place a cooling rack on a baking sheet lined with foil. Spray the rack with nonstick spray.
Place the chicken, mashed potatoes, parsley, salt, garlic powder, onion powder and parsley in a food processor and pulse until smooth and combined.
In a shallow bowl or plate, combine the panko and Parmesan.
With moistened hands (or spray hands with nonstick spray), roll 1 tablespoon of the chicken mixture between your palms and flatten into a "nugget" shape. Gently press the nugget into the panko mixture to coat. Set the nugget on the prepared rack/pan. Repeat with the remaining chicken mixture. Lightly spray the nuggets with cooking spray.
Bake for 20 minutes, or until crispy outside and cooked throughout. Serve with ketchup, ranch dressing (or the Veg-Wee Dip shared in the Weelicious Lunches cookbook).