Nissan some where will have the key details, you could try your local dealer, some may charge for this service !
Some dealers just cut a key from the chassis details.
I suggest that you go to edit in the forum and delete your chassis number from your previous reply! JUST IN CASE !
You can always PM it to whoever needs it.
We have a member on file who offers Nissan discounts, so he may be able to help you.
I assume that the original key fitted all locks including the rear door, so it most probably the original key number. Which is a good thing.
Also from your information, the key won't have a chip inside.
I guess more members will be along shortly, not many members are on line yet.
Best regards,
Rustic