Opened a GitHub issue:

https://github.com/pindab0ter/UPSFriendlyNixieTubeDisplay/issues/5

I'm experiencing the same thing. They worked yesterday, today I updated to 2.0.32 on my PC and they stopped working.

It seems that while in remote view they will not update their display. I flew back to Nauvis to investigate why they displayed I had 12k cryo science stockpiled when in fact there were none. At one time there were indeed 12k in storage but research chewed them up. When my character arrived at the nixie tubes they finally reflected 0 cryo science.

On the space platform they will occasionally show the correct value when placing a new nixie tube but then it never updates afterward. Oddly, when removing the wires from the tube it will continue to show a value.

Other mods:
Editor Extensions,
Factorio Library,
Far Reach,
Max Rate Calculator.

Yep, copypaste from my Github comment:

Okay, I found the exact scenario that causes the nixies to stop updating.

It happens whenever all players on a server are in remote view. Including the case of just a single player on a server, in that case it will never work in remote view since 1 player = all players.
This seems to be per-surface though. On a space platform, where there is no player, the nixies do not update automatically at all.

Fixed the issue. The mod did not consider surfaces that are viewed through Remote View as visible/watched.
I fixed it and, since I have no patience, uploaded a fork that includes the fix. Might be removed though if the changes are merged back into this mod.

https://mods.factorio.com/mod/UPSFriendlyNixieTubeDisplayFixed

PR: https://github.com/pindab0ter/UPSFriendlyNixieTubeDisplay/pull/6

Thank you for reporting the bug and putting in a PR, great work!