If you want a solid 100+FPS at 1440P, the GTX 1070 will not cut it at all. You need at least a GTX 1070 Ti - 1080 Ti to get that level of performance.
That is at ultra settings, if you dial down to high and medium settings, sure you can get 100+FPS. But that's up to you.
I personally have a GTX 1080 and a 1440P screen and in order to play anything close to 100fps i have to dial settings down to high or even some stuff to medium. But I don't really care, stuff at high settings basically looks just as good as ultra to me.