While I've yet to actually restore it because I'm having troubles getting the exfat update, I've been able to confirm that my reconstructed 10 part dump my NAND from ReiNX is viable with HacDiskMount using my Switch's keys from biskeydump. It should function just fine so long as your Switch didn't fall asleep while dumping and you had enough room on your SD card.
Update: My ReiNX backup worked. Dunno if I'll escape a ban or not, but my reconstructed rawnand and boot files wrote without issue using memloader and Hex Workshop. The news that I left unread before the backup and read after the backup became unread again, so at the very least, the NAND was perfect.