At least to a speaker of modern standard German Kitsch is not discernibly derived from another word.
The Wikipedia article about Kitsch mentions an origin among 1870s Munich art dealers and a possibly derivation from dialectal kitschen = sweeping [a floor, the sidewalk etc]. The Duden dictionary (doorstop edition) that I just consulted, OTOH, refers to an archaic dialectal word kitschen = to smear.
I don’t know about Munich dialect but there sure is no related word in standard German.