Coming up empty so far. Non-contemporary sitcom starting between 1960-1975…
M * A * S * H - could be a non-American minor character - I thought about asking “Asian” for my last DQ, but wanted to rule out an animal
Happy Days - I think they were all American. Certainly any Cunningham was.
Laverne & Shirley - started after 1975
When Things Were Rotten - not long running
F-Troop - black & white, all American or native American characters.
Flintstones/Jetsons - not live action
Hopefully one of the remaining DQs will shed some light.
Hogan’s Heroes - but he’s not European
Gilligan’s Island - maybe a one-shot Pacific Islander character? But no, contemporary.
I Dream of Jeannie - somebody from the Middle East in one of the scenes from Jeannie’s history?
To restate it, we have a male fictional character introduced between 1960 and 1975 on a long-running period sitcom set outside the US (so likely Hogan’s Heroes or MASH), who’s African, Asian, Australian, or Canadian, and known by a nickname the last word of which begins with C. The character may or may not actually appear in person on the show.
Nitpicking: he could be Oceanic, and his nickname is only one word that starts with a C. Color TV shows didn’t really start until the mid-60’s. And it’s a non-genre sitcom, which doesn’t add much.
None of those were long running, though. I can’t remember any that lasted more than one or two seasons, although they were endlessly repackaged and reran throughout my 70s childhood. Even their most recognizable one, H.R.Pufenstuff, ran only a single season + a theatrical movie.