Using two different Nginx server blocks would be the right approach if you are serving one of the sites from a different domain or sub-domain. If you'd like to serve the Django app from a sub-folder, you will need to make use of a location directive in the same server block.

The details may differ for your exact setup, but here is a basic example of serving a static site from the main domain and a Django project from a subfolder:

upstream app_server {
    server unix:/home/django/gunicorn.socket fail_timeout=0;
}

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;
    server_name example.com;

    root /path/to/pelican/files;
    index index.html index.htm;

    client_max_body_size 4G;
    keepalive_timeout 5;

    location /app/static {
        alias /path/to/django/static/files;
    }

    location /app/ {
            rewrite ^/app/(.*)$ /$1 break;
            proxy_set_header X-Script-Name /app;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $host;
            proxy_redirect off;
            proxy_buffering off;

            proxy_pass http://app_server;
    }
}

Two very important parts in the location directive that are specific to hosting from the subfolder are:

            rewrite ^/app/(.*)$ /$1 break;
            proxy_set_header X-Script-Name /app;

This ensures that the Django app will generate URLs with the correct prefix in the path (e.g. example.com/app rather than example.com).

Hope that helps point you in the right direction!