IIRC, Australia and maybe Mexico allow for 0W-40/10W-40.

 

I noticed this issue with my '20 Frontier recently. Nissan lists 0W20 as the oil for the 3.8L VQ, but my local dealer has been using 5W30 on each oil change. I asked them about it last week and the SA told me 5W30 is what Nissan recommends and is the oil the 3.8 gets at the factory. It seems unlikely when any source you look at online says the recommended oil is 0W20, but as Cali noted, the most important info about oil viscosity is the temperature range they cover for your motor and 5W30 is fine for my engine as well, so I let it slide. When I do my own changes, it will get 0W20. I suspect MPG may be a bit better with 0W20.

 

In Australia, 10,000km service intervals we used to use 10w30, now, with newer models with 15,000km service intervals we will use 5w30 for all petrol models.