How can I create dynamic ssl certificate key location in nginx conf file?

I have many domain names folder in /etc/letsencrypt/live/ this location with cert pem and cert key file. I want to serve any type of domain SSL key that in my /etc/letsencrypt/live/ directory and I programmatically add different domain in this directory.

my nginx.conf file

server {
    listen 443 ssl;
    server_name default_server;

     map "$host" $domain_name { ~(.*)\.(.*)\.(.*)$ $2.$3; }

    ssl_certificate /etc/letsencrypt/live/$domain_name/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/$domain_name/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

    client_max_body_size 20M;
...
}

But when I request a domain I got the error. No such file or directory:fopen('/etc/letsencrypt/live/default_server/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file) while SSL handshaking So $domain_name variable not transletting correctly it turns into default_server . How can I achieve this type of things. Thank you!.