Works like a charm. I've been using that setup regularly for close to 15 years.
With the 2.1cm lens (21mm), depth of field is enormous, so it more than covers the slight focus difference between Zeiss and Nikon focus mounts.
Also, unlike with the Contax IIa/IIIa, you don't have to worry about lining up the lenses rear rotating light-baffle collar. The Nikon is much larger inside.
If you find you like shooting with it, you might want to get a Leitz or Cosina-Voigtlander 21mm finder.
Nikon S2, S3, S3-2000, SP, SP-2005 / Kiev 2a
Biogon 21/4.5; CV 21/4; CV 25/4; CV 85/3.5; the following Nikkors: 2.8cm/3.5; 3.5cm/1.8 (1956 and 2005 versions); 5cm/1.4; 8.5cm/2; 10.5cm/2.5; 13.5cm/3.5
Soviet lenses: Orion 28/6; Jupiter-12 35/2.8; Helios-103 50/1.8; Jupiter-8 50/2