As with most cars, reverse is not synchronized. That means in order to shift into reverse without grinding, all the guts inside the transmission must be dead still before the reverse teeth engage or they will clash.

When the clutch is depressed, even if everything is adjusted correctly there is often still enough drag on the clutch disk to keep it spinning with the flywheel and pressure plate unless there is something that makes it stop. This is even more prevalent when the tranny oil is hot and thin. The friction from cold thick gear oil will stop the spinning quickly, but hot thin oil may not.

Shifting into any forward gear will stop the internals, and then a quick shift into reverse should go in without any grind.

Thanks for all the suggestions.  Have taken the console and underneath boots off and gotten to the shifter mechanism.  Removed that and found that the bushings around the pin holding the shifter were completely gone.  Contacted my local Nissan dealer and had the bushings two days later.  Thanks, Cliff, and others with suggestions.  It is all back together now and shifting is much more precise as the slop in the lever has been eliminated.  There is some stiffness in moving the lever to the right for reverse, but I have lubed it well and will see if the lube will work it's way into the shaft area.  Thanks again.

a quick tip to tell if the bushing on that pin are shot, does the shift knob rotate at all? if there is ANY rotation noted then the two side bushings are shot.