Hey Daryl.
Thanks for the note. Everything is being served on 8181.
Also tried every permutation of this I could think of:
... and similarly with the BOSH_SERVICE var (using 8181). Nothing seems to work with nginx.
I wound up setting it up with Apache, and all's well. Was trying nginx because I thought it'd be easier from scratch, but it's already as much of a pain as Apache (which I know pretty well).
Could be issue with reverse proxy? Apparently nginx lacks anything like ProxyPassReverse. I don't know if OpenFire is using any of the headers affected by ProxyPassReverse, as I haven't tested if the Apache setup works without that, but that could be the issue.
If anyone figures it out, maybe throw a note up here.