There are "per channel" I/O level jumpers inside the Multiface (mentioned in the manual - look for the original MF manual as the MF-II added front-panel switches for this function).

https://archiv.rme-audio.de/download/mface_e.pdf

Page 42 :-)

See if the channels might be set to "lo gain" and swap them to "-10dBv" setting - this will net you an instant jump in level (approx +17dB) w/o any additional noise from the RME.  If that is too much, compromise on the standard "+4dBu" setting...

Yep - Not actual switches, but little jumpers that need to be placed appropriately.  Take your time and follow the directions in the manual (actually on page 78 as you probably saw) - getting the top PCB out can be a bit of a pain, but it will come out w/o too much of a fight (just don't pull anything too hard or you might dislodge the ribbon cable).  You will need to remove the little ADAT Sync (DB9) screws as well...

Each channel has its own jumpers, and input and output are also independently adjustable (a total of 16 jumpers to fiddle with!).  I'd probably start by simply jumping inputs 1/2 to -10dBv for your Nord, and go from there as your gear connectivity dictates.  Since the "-10dBv" setting means "no jumper", you can simply leave the jumper connected to one of the three pins to avoid losing the jumper (as long as it is only connected to a single pin it is the same as completely removing the jumper, but you'll be able to find the jumper next time you need to change levels ).

Enjoy!

Hey.
I just did this and it works well.. was hard locating the Jumpers as ive no idea what i was looking for. but once i figured out what / where they were it was simple.
thanks again