Marinate the chicken: In a bowl, combine cubed chicken with salt, soy sauce, cooking wine, black pepper, and cornstarch. Mix well and let it marinate for 10–15 minutes.
Make the tartar sauce: In the same time, hard boil two eggs for about 10 minutes, then transfer to an ice bath to cool. Peel and chop the eggs, then mix with mayonnaise, rice vinegar, salt, and black pepper until creamy. Chill in the fridge until ready to use.
Cook the chicken: Heat oil in a pan over medium heat. Add the marinated chicken pieces and pan-fry for 4 minutes on each side, until golden brown and cooked through.
Add the nanban sauce: Pour the nanban sauce ingredients directly into the pan. Cover with a lid and let the chicken simmer for 2 minutes so the flavors soak in.
Serve and enjoy: Place the chicken over a bed of freshly shredded cabbage and finish with a generous spoonful of tartar sauce on top.