So here it is.
My template is getting out of hand at the moment, so I stripped it down bare for educational purposes haha 
What this basically does is convert the track name or its color to a SysEx message. On the receiving side, TouchOSC decodes that through a simple Lua script and changes label/color to a child object.
Some preparation first. This following compressed folder has to be extracted in
C:\Users<YourUserName>\Documents\Steinberg<Nuendo or Cubase>\MIDI Remote\Driver Scripts\Local
…basically, in wherever your Cubase/Nuendo reads the MIDI Remote JavaScripts. So when you are done you should have a folder called
C:\Users<YourUserName>\Documents\Steinberg<Nuendo or Cubase>\MIDI Remote\Driver Scripts\Local\HexFM\TouchOSCTest with just a JS file in it.
HexFM.zip (1.4 KB)
And this is the TouchOSC preset to go with, which you can put wherever you want.
TouchOSC Nuendo Sysex.zip (1.8 KB)
There’s a few things to set up both in TouchOSC and in the MIDI Remote sections to get it to work:
- Obviously connect it to the port of your choice (“TouchOSC” or “TouchOSC Bridge”) in the MIDI Remote
- Activate those ports on the tablet/PC/dust bucket you’re using.
The Lua script that you will see takes a Sysex from Nuendo, checks if it starts with the hex version of “NAME” or “COLR”, and then takes the rest of the SysEx and treats it accordingly.
Remember this is kind of a hack - I could do a better job at passing colors, but a 0…255 range worked well enough for me and kept the SysEx short.
Let me know if it works 
PS: None of this would have worked without @Jochen_Trappe’s help. I also had significant input in my own, bigger template from the guys behind the community-run TouchOSC Discord server