Since it's a new IP and all I don't see boosting sales THAT much, but still, we may see a noticeable boost hopefully.
Anyway, I think the most important thing Splatoon has to do is getting really good reviews and achieve strong sales even if it's not a system seller. This way it can strengthen Nintendo's image a bit since people's been saying that they only live out of Mario, Pokemon and Zelda for a long time. A new strong IP is what Nintendo needs. The only thing that worries me is Splatoon not having an easily recognizable mascot, which is crucial to promote the game more easily.







