Wel, to me nos means literally new old stock so it should be in its original, unopened packaging. Open package does not qualify to me, nor without package.
Also, nos with open package is whatever you value the nos story: you can't verify. So in your case its still nos after a quick check if it works i guess.

To me this wouldn't need an issue to the object, I only buy stuff to be used. On the other hand,i wouldn't even buy something for the nos state.....

To me, open packaging is not NOS unless it was originally in a tray, and if it has been tested, that stops it from being NOS, as it has been used, however briefly. A boxed processor should be still sealed if sold as NOS.

Okay, my thought was that it was also tested once in the factory back in QC. But you're right, it's very difficult to understand. AMD CPUs in particular always look very good on the outside after use. You can't tell if they have been used and even OC.