It will be a very good year for Software in Japan.
Last year had Sun and Moon, which were the hottest selling games over there since Monster Hunter 4. But Final Fantasy and Yokai Watch underperformed, sadly.
This year they're getting a new main series multiplatform Dragon Quest, Pokemon Ultra Sun and Moon, Splatoon, and the release of the Switch really sparked some sales for Zelda and Mario Kart (both will probably crawl into the million mark, good!).
Add other well selling games such as Nier, and other big games that could make an impact such as Mario Odyssey, Monster Hunter XX, and Gundam Wing... And we'll probably see an improvement over last year.
I could definitely see the year end chart falling into place like this:
1. Dragon Quest XI
2. Pokemon Ultra Sun and Moon
3. Splatoon 2/Monster Hunter XX
4. Monster Hunter XX/Splatoon 2
5. Mario Kart 8 Deluxe
Edit: Monster Hunter XX was released this year. For some strange reason I thought it had been released last year.