It depends on the model and the location of the bike, but I absolutely disagree that it is worth nothing.

At eBay, search on Nishiki, filter to the "Sporting Goods : Cycling" category, show completed items, and sort by price. Recently vintage Nishiki bikes have sold from $280 (+$60 s/h) down to $30 (+$100 s/h).

In most locales, a very good condition, rideable bike is worth at least $60 on Craigslist.