Create the Meat Emulsion: In a food processor, combine the chicken breast chunks, 2 tsp kosher salt, 1 tsp white pepper, 1/2 tsp MSG, and 1 tbsp corn starch. Blend on high until the meat breaks down and forms a fine, sticky paste. (Note: If using pre-ground chicken instead of a food processor, see the notes below).
Shape the Nuggets: Using a cookie scoop, portion out the chicken paste. Roll each portion into a ball, then flatten and pinch the edges to form classic nugget shapes.
Coat and Freeze: Toss each shaped nugget into the reserved cup of dry corn starch until completely coated. Tap off the excess, place them on a parchment-lined baking sheet, and place the tray in the freezer while you prepare the batter and oil. Freezing sets the shape and prevents the interior from overcooking in the fryer.
Heat the Oil: Fill a heavy-bottomed pot or deep fryer with frying oil and heat to exactly 350°F (175°C).
Mix the Tempura Style Batter: In a large mixing bowl, whisk together the AP flour, 1/2 cup corn starch, 2 tsp kosher salt, 1/2 tsp white pepper, 2 tsp paprika, 2 tsp garlic powder, 2 tsp onion powder, and 1 tsp baking powder. Right before frying, gently pour in the sparkling water and whisk lightly until just combined.
Batter and Fry: Working in small batches, dip the frozen, cornstarch-coated nuggets into the wet batter, letting excess drip off. Carefully drop them into the 350°F oil.
Cook to Perfection: Fry for 4 to 5 minutes, flipping halfway through, until the exterior is a crispy golden-brown and the internal temperature of the chicken reaches 165°F.
Drain and Serve: Use a spider skimmer to remove the nuggets and let them rest on a wire cooling rack so they stay crispy. Serve hot with your favorite dipping sauces!
