I am sorry you are having this problem but let help you.
While Intel has not tested and validated Intel® NUC on your Linux version, we know that other customers have successfully installed it.
Intel suggests you check your Linux Ubuntu’s website and forums at http://www.ubuntu.com/ for peer assistance with this installation issue.
Here you can get more information about supported/ validated Operating System:
When it crashes/hangs do you get any artifacts on the screen? On my NUC(which isn't the same model as yours, mine is DN2820FYKH) I sometimes get green artifacts intermixed with the screen pixels when it hangs/"crashes".
Also can you reproduce the hang/crash? I get frequent crashes when starting 2 instances of Minetest(which are active on 2 different worlds at once) which use lots of 3D acceleration. I use oibaf ppa but I've not yet tested the Intel(R) Graphics Installer for Linux* (1.0.8 rel. 17 Mar 2015) by the Intel Open Source Technology Center.
The crashes/freezes/hangs I get cause my computer to immediately shut down, crash with graphical artifacts on the screen in frozen state or cause my display to lose contact with the computer and "go to sleep".
Have you tried oibaf drivers before?(learnt about it from phoronix)