Japan has a way of making daily tasks exceptionally convenient - it's probably why there are so many convenience stores here. Another thing I've noticed is just how many train stations have a host of different amenities attached to them, including full shopping malls. At Nagaoka Station in Niigata, the CoCoLo mall makes it easy to indulge in some retail therapy, grab a bite to eat, or even get a manicure, dental checkup, or a new pair of glasses while you're waiting for your train.
On the first floor of CoCoLo Nagaoka, there's a section dedicated to local souvenirs if you want a memento from your time in this part of Japan. You'll find things like bottles of local sake, koshihikari rice (the pride of the local area!), and products from Yasuda Yogurt, a Niigata-based dairy company. There are also various restaurants on the first floor, including Asahiyama which is inspired by the design of sake breweries. Here you'll find a range of seasonal dishes, many of which contain local vegetables and fresh fish from the Sea of Japan. There's also Kojima-ya where you can get your fix of hegi soba, Torijin for yakitori, and many more.
Up on the second floor, you'll find a branch of the CanDo 100 yen store chain, and Muji, famous for their range of minimalist-inspired products. Jupiter Import Foods has various international foods if you're missing something from home, and Jins is an eyewear store chain, where you can get an eye test and a pair of glasses with an incredibly fast turnaround time. If you want to learn more about Niigata's sake brews, check out the Ponshukan museum (also on the second floor), where you can sample five different varieties for 500 yen.