Add the chicken breast to a food processor and pulse until it reaches a coarse texture. Add the cornstarch, garlic powder, onion powder, black pepper, salt, baking soda, and ice cubes. Blend until the mixture becomes smooth, sticky, and starts clinging to the processor blade.
Transfer the chicken mixture to a plastic or zip-top bag. Shape it into a log, then seal the bag.
Freeze the chicken log for 3 hours, or until firm enough to slice.
Remove the chicken log from the freezer and cut it into slices about 2 cm (¾ inch) thick.
Prepare the batter. In a large mixing bowl, whisk together the flour, cornstarch, baking soda, salt, and water until smooth. The batter should be lump-free and thick enough to coat the chicken evenly.
Heat enough oil in a deep pot to 170–175°C (340–350°F). Dip each chicken slice into the batter, making sure it is completely coated. Carefully lower it into the hot oil and fry for about 3 minutes, or until the nuggets are crispy, golden brown, and fully cooked. Fry in batches to avoid overcrowding the pot.
Transfer the fried nuggets to a wire rack or a plate lined with paper towels to drain any excess oil.
Serve immediately while they're hot and crispy with your favorite dipping sauce, such as ketchup, honey mustard, barbecue sauce, or spicy mayo.
