Rinse the potatoes well, then chop in half. Put in a heatproof container and microwave. Peel the skin.
Mix all the ingredients for the coating. Dredge the potatoes and deep-fry in 170 oil. (If it's too hot, the potatoes will burn before the coating has finished cooking.)
Chop in half, pack in desired bento containers with the chicken nuggets, and serve with mustard and ketchup.
Three-Colored Bento with Chicken Thigh
Beef Rolls Bento
Salmon Teriyaki Bento
Fried Okra Bento