You should be fine with that - but I use 5-30. Mobile 1 is a decent oil so you'll be pretty well protected. Iowa gets pretty cold so the 0-30 shud be fine...

did anyone check the owners manual for Nissan's recomendation?

Exceptions? There are none.

I run Mobil 1 0W-40 in my QX4 (manual recommends 5W-30 just like my M did) during the winter and I think it starts better in the frigid temperatures.

You will not damage your engine running a zero weight oil during the winter.

I use Mobil 1 0W-40 regularly ... even though I am not in sub-zero weather. This is an excellent oil and highly recommended by an oil expert I know - which is why I use it instead of "regular" 5W-30.

Of course, 0W-30 will be fine for winter months in Iowa. BTW, the manual does tell you that 5W-30 will work to pretty low temperatures as well.

To the OP: you should get 6 quarts (six 1 qt bottles, or one 5 qt plus an extra 1 qt) of oil for a change, since the M45 takes 5 7/8 quarts with a filter change (and you do that at the same time too, right? Right?? )

Z