It is an optical shrink of 16FFC - same design rules but scaled down - also I believe nVidia have access to 9 track libraries over the normal 6? which is allowing them to squeeze a bit more from it.
While the more suited 7nm+ w/ EUV won't be available until about another year TSMC is catering for all market segments with their standard and HPC, etc. implementations of 7nm including GPUs like Volta - people already have products of this kind of requirements in testing with TSMC.
No, they don't, and Volta is categorically a 12nm (16nm) SHP product.
It would require total redesign (i.e. different architecture) to have such a massive optical shrink to either 10nm or 7nm, and a lower power node.
If you weren't trolling and actually believed Volta could or would use a TSMC 7nm or 10nm process, within its design lifetime, explain why it won't, and will face a 2 node deficit to AMD's competing product.