In a small saucepan over medium heat, combine the ponzu sauce, sugar, and cornstarch, stirring frequently until the sauce thickens, about 5 minutes. Set aside and cool.
Put the egg in a bowl, the flour in another bowl. Combine the nuts and panko in a third bowl. Season the three bowls with salt and pepper.
Holding the tail, coat each shrimp evenly with flour, then dip in the egg mixture and place in the nut mixture, turning to coat well. Repeat the steps until all the shrimp are coated.
Pour enough oil into the deep fryer or a deep pot to fill at least 2 inches (5 cm). Heat to 375°F (190°C) or until a 1-inch (2.5 cm) cube of white bread turns golden brown in 30 seconds.
Fry 3 or 4 shrimp at a time, turning once, until golden brown, about 1 or 2 minutes. Using a slotted spoon, transfer the shrimp to a plate lined with paper towels.
Serve hot with the ponzu glaze.