I thought that the word honcho as in head honcho (big leader / big cheese) came from Japanese. The OED and the Online Etymology Dictionary both say that it comes from the Japanese word 班長 (hanchō) or squad / team leader, and that it was borrowed by American servicemen in Japan and Korea in 1947-1953.
However, according to The Basque History of the World by Mark Kurlansky, which I’m reading at the moment, the word honcho is a version of the Basque word jauntxo /xaunʧo/, a wealthy. powerful, rural landowner – a word with a ironic, negative undertone. From jaun (sir / lord / god). This sounds kind of plausible, though I haven’t found any other sources which make the same claim.
The book is interesting and includes quite a few bits of Basque language, and even some recipes. It is also somewhat biased in favour of the Basques.