Yes, you can just configure the spdy plugin for nginx and place it in front of your webserver. Easy and we measured significant load-time wins.
In practice, if you already have an SSL server, just add the "spdy" to the listen line like "listen 443 ssl spdy;", restart and you are done[1].
Then making it proxy request is just one location definition with "proxy_pass"[2].
[1]: http://nginx.org/en/docs/http/ngx_http_spdy_module.html