You'll need to use nsopenssl.so (put its config section into your aolserver config, as set out in the INSTALL).
If you've done all that, then you may have to comment out the nsssl module config (or the load section) if you have your certificates where nsssl expects to find them. It uses these as a signal to load itself, and that could be the cause.
Also, in the config section which is added to the aolserver config, I had to change the
ns_section "ns/server/{$servername}/module/nssopenssl"
to
ns_section "ns/server/{$server}/module/nssopenssl"
