Well there isn't really an uptime of openssh. you can check that it is active or how many connections it has. Or can grab the last time it was restarted by looking at
ls -l /var/run/sshd.pid
-rw-r--r-- 1 root root 4 2012-12-15 21:26 /var/run/sshd.pid
That file is updated when the daemon starts/restarts. So you can calculate based on that.
For nginx you can install the status module (http://wiki.nginx.org/HttpStubStatusModule) and then use that to get some information, but alas uptime doesn't look to be there. Could probably use the same idea of looking at the nginx pid files, but that will just tell you since the last restart etc. and not 100% indicative of uptime.