snap install nextcloud

nginx config

server {
    listen 80;
    server_name cloud.arctic.cat;

    location / {
        proxy_pass_header Server;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_pass http://127.0.0.1:81;
    }
}