Hmmm . . . Sorry to read and see your situation. I trust you are doing well and hope that everything resolves itself quickly for you.

 

I totalled my 04 G 5 months ago, it was a leased G as well.

Basically, you are not supposed to get any $$ money back,
not even your down payment, but if you are still planning to get another G,
then call the Nissan HQ and request something called substitutional collateral.
They will, not promised, try to replace you with a similar G.
OR
You can be a total jerk to them and ask for the difference between the amount the insurance company wrote to nissan and the total cost of the car. Usually 3-5k difference there. I got my dealership involved in this and received 2,400 back from Nissan. My dealership also offered me invoice price on my new G (Financed it this time).

If you'd like to make some more cash out of this deal, go to your local bodyshop and see if they are interested in your totalled G and buy the car back from your insurance company, then sell it to the bodyshop.
One of my local bodyshop, I've know them for years, offered me 1,000 profit to purchase it back and sell it to them.