[OS X TeX] Chinese character subscripts in TexShop

[Nathaniel Pearson]

Working with TexShop, I'm trying to typeset a small number of Chinese
characters as subscripts for Roman characters.  The problem of
inputting and/or outputting Chinese characters in TexShop seems to
have popped up often on this list and elsewhere.  I've tried in vain
to implement various publicly posted solutions: specifying UTF-8
encoding; invoking packages like fontspec; etc.  But no dice.

I suspect that part of the problem is how I'm entering characters into
the .tex file in the first place.  I've tried cutting and pasting in
an already rendered character, for example, and it pastes fine into
the input code, but is not rendered in output under any of the various
posted methods.  Alternatively, I've tried to figure out a way to
include the character's Unicode identifier (U-9670, fwiw), but am not
sure how to do so or even whether that's a viable approach.

Any advice would be appreciated; thanks.