Another one back from the dead. I figured out how to do this on my 2018 SV this evening, not sure if it applies to the previous gen 2014+.
The 2018 seats are as described above, the bottom seat pan mounts to the rail using a bolt inside the cushion- the nut is integral to the rail/adjustment mechanism. This makes accessing the bolt impossible with the cushion in the way.
Thankfully it's easy to lift the front edge of the cushion without damaging anything. There is a plastic channel that clips the upholstery onto the front lower edge of the metal seat pan. Starting from one end, gently work the channel down and forward to unclip, and continue along the edge until the front "flap" of upholstery is free. From here you can lift the front 4" or so of foam pad to access the two bolts. Sounds way scarier than it is- it goes back together very easily.
A T40 torx is required to loosen the bolts. I used a T40 1/4" bit in a 1/4" socket on a small ratchet, but they unscrewed by hand after the first turn or so. There is enough length on the bolts to add ~10mm of height. I'll run it this way for a while, but I suspect I'll buy longer bolts for more angle in the near future.
Thanks to those who figured this out originally. This mod goes a long way to alleviate the close pedals/far wheel seating position. Next will be figuring out how to get the seat lower. I feel like I'm sitting on this car instead of in it.
2018 Leaf SV w/AWP
2001 Tundra 3.4 Turbo on 34s - Expedition Rig
2015 Leaf SV w/QC (leased)