Proxy HTTPS without certificate with nginx

Is it possible to setup nginx so that it proxies a HTTPS connection without decrypting it? I'm talking about something like this:

server {
    listen 443 ssl;
    server_name example.com;
    location / {
        proxy_pass        https://localhost:8000;
        proxy_set_header  X-Real-IP  $remote_addr;
    }
}

I know, that nginx most likely will need a certificate to add the X-Real-IP header, but can I re-encrypt the proxy?

My motivation behind this is, that I want to pass the traffic through to my Node app, that has SPDY enabled. But for being able to use SPDY in Node, I need the decryption to reside inside the app.