Lukas, you're of course right!
My mistake, I see so many times the "ERR_SPDY_INADEQUATE_TRANSPORT_SECURITY" error that I forgot there was another one which is completely different.

Shahzaib, I'm very sorry, I can't help you :-(
As said by Lukas, have you tried others files than the mp4 we see in your capture? Like images or just plain text.
And also have you tried compiling nginx without "--with-http_mp4_module"?

Best Regards