Is it really possible to run JIRA in HTTP mode and add a nginx proxy in front of it terminating the HTTPS connections? I have tried it a few times with JIRA 5.2 and discovered I couldn't: I had to run JIRA in HTTPS mode (Tomcat configured to serve HTTPS) so JIRA would correctly reference https:// URLs.
Just yesterday I upgraded this system to JIRA 6.4.10 and thought that would possibly be a solved issue. So I once again configured Tomcat 7 to serve HTTP only and configured nginx with SSL. Once again, I saw JIRA pages references HTTP URLs instead of HTTPS URLs, even though the Base URL was always set to be HTTPS.
The funny thing is that this works beautifully with Confluence and Tomcat 8.