I had read in a catalogue that the Georg-August-University of Göttingen Department of Musicology hosts a collection of musical instruments, including two Nasenflöten. And thus, I wrote to ask for pictures.
Herr Dr. Klaus-Peter Brenner, the Curator, kindly took the time to make photographs and to send them to me.
There are only two nose flutes in the collection, but they are interesting. The first one is a Wunderflöte: it is a second generation Wunderflöte, the same model than the one drawn in Siegfried Wolf's book or featuring in Piet Visser's collection. The Göttingen sample is in a quite good shape, and still showing its nickel plating:
The other flute is a simple chinese plastic Swan, but it shows the rather rare particularity of a translucent airway cap. We knew some Swan Nasenflöten with a translucent part, but it was the main shield.