I must admit, I had never heard of this word before I saw this, so I did a search on Google and found the following:
Honcho is an informal word that was coined in the United States in the 1940s to mean "officer in charge," becoming especially popular with U.S. soldiers during the Korean War. Honcho comes from a Japanese word for "group leader," hancho, from han, "corps or squad," and cho, "head or chief."