You can try visiting these nightlife districts: for example, Roppongi is very lively at night. Shinjuku is also famous, as is Shibuya, so no need to mention those. Shimokitazawa is a place young Japanese people often go to. Akasaka is a food paradise, especially if you're a food enthusiast.
Absolutely, Japan offers a diverse range of natural attractions including Mount Fuji, Hakone's hot springs, Nikko's serene landscapes, the Jigokudani Monkey Park, traditional Shirakawa-go village, Aso Caldera with Mount Aso, Takachiho Gorge, and the calming Oirase Stream.