It can run games at 4K, absolutely. But max settings are very unlikely to be achieved (with playable FPS), in all but a select few titles.
A GTX1070 is a High/Ultra 1440p card, or Low/Medium range 4K card....
To aim for 4K, max settings & 30+FPS, you really have to look at a minimum GTX1080, preferably a 1080TI.
What's your budget overall?
The rest of the build is solid enough overall, but has some sizeable flaws:
*The 7600K is unlocked, so can be overclocked. Paired with a B250 board though, you eliminate that option. Either pair a 7600K with a Z270 board, or a 7500 or 7600 with the B250 board.
*The NEX lineup is not the greatest. a
Seasonic G650 or
Rosewill Capstone G650 would be quality 650W options in the same pricepoint - although even a
SuperNOVA G3 550W would be sufficient for that rig.