I found the placement of the ISO button a bit odd, but Easy ISO is a good option.
Most of the Nikon cameras are pretty easy to use without taking your eye off the viewfinder. With Easy ISO implemented, you can see the result of setting changes to ISO, AF (all settings), aperture, shutter speed, and exposure compensation through the viewfinder. The implementation is pretty consistent across all bodies since the D7000 a couple of years ago. Only the ISO function is different between the D7000/D600 and other bodies and that's partly because of the size of the body.