I encountered the same mpcie card whitelist nuisance on the Lenovo m73 Tiny. Turns out there that you can just update the serial and model number to "INVALID" and it will then let you boot with a non-whitelisted device, albeit with an angry beep and warning message.
Apparently it's possible to add the pcie device identifier to the whitelist, but it looks like a very fiddly process and I didn't really care about the minor issues resulting from the cruder approach:
https://www.reddit.com/r/homelab/comments/lx7d8f/pfsense_len...
Apparently it's possible to add the pcie device identifier to the whitelist, but it looks like a very fiddly process and I didn't really care about the minor issues resulting from the cruder approach:
https://www.reddit.com/r/Lenovo/comments/dcf0lw/comment/fbpy...
No idea if any of that works on the X1 Nano, but you never know.