Hippari Dako
on main street just before the shrines. enshrined in lonely planet, every other foreign tourist to nikko seems to stop here for yakitori japanese chicken kebabs and noodles, so you might as well join the crowd. every available space is plastered with business cards and scribbled recommendations from visitors. their menu contains several vegetarian options as well. dishes ¥500 and up.
Yuba, the 'skin' that forms on top when making tofu, seems to be everywhere in Nikko. Even if you're not a fan of tofu, it tastes pretty good, especially with soba buckwheat noodles in a soup broth. Yuba is also one of the most typical edible omiyage from Nikko.
Gurumans Wagyu
Wagyu japanese beef steak restaurant in Nikko. 3-4 minutes taxi from Nikko station. Reservation needed. The dress code is not too strict, but no sandals, no running wear.
Shiawaseya Hakuun
A great place to have a cup of tea and something sweet whilst waiting for your train or bus. Endless green tea comes with everything. Try the anmitsu ¥400 a dessert made up of fruit, bean jam and molasses.
Farmers market shop
Off the tourist trail this is a good place for some fresh fruit and veg at non-tourist-trap prices. Turn right as you leave Tobu Nikko station, right again at the traffic lights, and it is the last shop on the right before the bridge over the river.