To me the word Tschim could be a plattdeutsch version of Jim.
The word Tschatsch sounds to me like Schatz an endearment meaning treasure or sweetheart.
My fathers name was George and he was always called Schorze.
My Plattdeutsch has not been used since the early 1950's also I still understand most of it.
Regards from Far North Queensland, Australia
Holger Asche