There is no such thing as "certificate under Nginx" or "a certificate under Apache". They are all equally applicable on anything: even on the web, at least for the mail server. There's just the finer points of how (and whether) packaging multiple certificates in one file or not. Lighttpd, for example, requires that the certificate file and the key certificate was in a single file that is achieved by simply concatenating two files.
This choice for 2domains, as the time of this Opera - they just Packed and you will receive the set that is needed under the selected option.
That is, do not need to bathe on this subject - have a certificate where you like and forward to victories.
rhianna_Yost answered on July 9th 19 at 10:46
Don't know what 2domains (I would go with them wouldn't work in principle).
But the nginx SSL works fine. In new versions there are and HTTP/2.