I've never thought much of Nissan's extended warranty choices. The only component I am unsure about is the CVT. Nissan's extended warranties extend coverage beyond hte standard 5/60K powertrain warranty to a maximum of 7 years and 100,000 miles. Thats paying $1000+ for 2 years and 40,000 miles worth of coverage. Not sure thats such a good deal. Everything, its a Nissan so its pretty reliable, I don't expect to ever have a problem with the minor stuff.
Update: not even sure if it goes to 100K, maybe just 84K. In which case 2 years and 24,000 miles worth of coverage for that cost, even less worth it.
But to each their own. I understand if purchasing it for peace of mind.