Part of me wants to say "You
can combine both programs, but if you are asking how to do it, you aren't ready to combine both programs." But, I won't.
You can sort of do NROL with HIAH concepts, but you'll need to make more than just surface changes.
If you'll notice, HIAH has fewer exercises per day than NROL does. That's because one major goal of HIAH is avoiding fatigue.
If you try it, here's a tip from my days doing Muscle Logic/EDT. In supersets/alternating sets/etc. I tend to get confused on how many reps I've done, so I take a pen and paper to tally your reps as I end each set.
There's more to just combining them, so I'll suggest that you do one, then the other, instead. If you combine them, and don't get good results, you'll never know what you did wrong.