The only one Nissan makes (as far as I've been able to determine) is the one behind the 3rd row. There are several that fit behind the 2nd row; the ones that look the best to me are made by Husky and Weathertech. The Weathertech tends to be about 30% more expensive. Be cautious on the Weathertech, though, they make one for behind the 3rd row too.
I still haven't decided what I'm getting yet. The reviews have been very positive for Weathertech, so I'm leaning in that direction at the moment.
Good luck and let me know what you decide.