Cut chicken into even 1-inch bite-sized pieces so they cook evenly and stay juicy inside after frying.
In a bowl, mix chicken with soy sauce, Shaoxing wine, garlic, ginger, egg white, five spice, salt, and white pepper until well coated. Let marinate 30 minutes to 4 hours for best flavor.
Add sweet potato starch to a bowl and coat marinated chicken lightly until pieces look rough and slightly dry for crisp texture.
Heat oil in a deep pot or wok to 325°F (165°C) and fry basil for 30–60 seconds until crisp, then remove and set aside.
Fry chicken in small batches for 1–2 minutes until lightly golden and cooked through, avoiding overcrowding to keep oil temperature steady.
Remove chicken and rest for 30–40 seconds so steam escapes and coating sets properly.
Increase oil heat to 375°F (190°C) and fry chicken again for 1–2 minutes until deep golden and extra crispy.
Toss hot chicken with fried basil, salt, pepper, and chili powder for final seasoning and serve immediately while crunchy.
