Yeah, the config looks really close to what I have running on other sites, so I'm not sure why it's not routing from 80 to 8080 yet.
Running this I can see nginx is on port 80:
netstat -nlp | grep :80
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 19820/nginx
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 19265/node
tcp6 0 0 :::80 :::* LISTEN 19820/nginx