Another thing that makes shopping in Nakano Broadway rewarding are the shops that are just a collection of glass cases. These cases are actually rented out by people who are trying to sell from their own collection. You can find some pretty rare items in the cases. The cases are periodically switched around, so there is likely to be something new each time you go.
The anime/manga goods are sold on floors 2-4, but it is my recommendation to venture into the basement for some good cheap eats. There are several restaurants in Nakano Broadway but my personal food favorites is the super-cheap seafood purveyor “Nakamura Suisan,” which sells to-go trays of sushi, and the Chinese dumpling store, “Mata Ashita.”
On the northwest side of the station there is a store complex called, “Nakano Central Park,” which has a pretty nice park by it and good lunch/dinner options. If you go as far as Broadway, why not visit Central Park as well?