Well, kinda. Not really chanting. Might not even be Latin either.
In FS2_Cinema2.wav, from the original FS2 soundtrack, there were some vocals which were quite obviously not in English. I don't think

would just throw any old random words in that sounded cool (though that's a possibility), so I figured they might mean something.
Anyone know what they mean?
(Also worthy of note, the vocals seem to repeat themselves in the ending cutscene of FS2 where Capella blows up.)
EDIT - here also pointed me to this
video of some random video game that uses the same choir sample.
EDIT2 - Yeah so I learned on IRC that everyone uses it and it's a stock sound.

Still would be interesting to know what they mean though.