I have just recently aquired a few IOR's and I have several Nightforces. Both scopes are awesome. Here is how I see it at this point comparing the IOR 6x24 Tactical and the NXS 5.5x22. I would have to give the IOR a bit of an edge on clarity, but I would give NF a bit of an edge on the turret feel and positive clicks, and the NXS a Huge plus on having more moa of elevation.
Thinking of what you will be doing, night shooting at small targets. I would give the IOR's Illuminated reticle an edge due to it has intensity adjustments right at your fingertips. For sure I am a HUGE fan of the IOR MP-8 dot reticle. I can center the floating dot on a 30 cal bullet hole at 100 yards. I see this reticle as a big plus for your type of hunting, and quick acquisition.
You may want to take a look at the IOR 4-14x50 also, I just got one of these with the 25moa top turret and it is an awesome scope. I think it will be perfect for my 6mm br build for a Long Range prairie dog and antelope rifle.
I don't think you can go wrong with a Nightforce or an IOR. But for sure get a look at the MP-8 dot reticle. I am sitting on too many scopes right now, and I need to sell a few but can't make up my mind what to get rid of.
Hope this helps.