The thing is if you try and get the retail price up, they may also try and raise the salvage price.... While you could try and wait for it to hit the auto auctions and get it for cheap(assuming you or someone you know has a license to purchase from them) you are taking quite a bit of a chance. If you really want it(I probably would in your case, especially knowing it has a new battery) I wouldn't wait for it to hit the auctions, try and talk to your adjuster and state you'd probably be interested in keeping it but was hoping they could drop the salvage price a bit. Personally I wouldn't mention the new battery but it's up to you, they may already know about it, I wonder if it's recorded somehow in CarFax? Nissan knows for sure, not sure who they pass it on to.
Worst case for $4k for a running Leaf and a basically new battery, I don't see how you could go wrong.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a