Running in oil. Pffft. I changed mine at a few thousand. I'm sure there is good quality control, the blocks are washed, components spotless but you never know, the odd one or two could slip thru the cracks now and again. After all, they are mass produced. Could be anything in there, casting sand, very small metal shards... I reckon it's best to change it and drive the thing like it was stolen, if something is going to give up due to poor assembly or manufacture it will be sooner rather than later and preferabley under warrentee.
Same goes for the drive line as well but a few thousand is probably a bit over the top, still, before Nissan recommend. Then as per after that.
BTW I was very careful changing the filter and oil using exactly the right spec oil even down to putting the exact shade blue factory paint dot on a genuine filter.