Ставим epel-release

yum install epel-release

Ставим phpMyAdmin

yum install phpmyadmin

Даем разрешения

chown -R nginx:nginx /var/lib/php/

chgrp -R nginx /etc/phpMyAdmin

Создаем конфиг в снипете

mkdir -p /etc/nginx/snippets

vim  /etc/nginx/snippets/phpMyAdmin.conf

location /phpMyAdmin {
 root /usr/share/;
 index index.php index.html index.htm;
 location ~ ^/phpMyAdmin/(.+\.php)$ {
 try_files $uri =404;
 root /usr/share/;
 fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock;
 fastcgi_index index.php;
 fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
 include /etc/nginx/fastcgi_params;
 }
 location ~* ^/phpMyAdmin/(.+\.(jpg|jpeg|gif|css|png|js|ico|html|xml|txt))$ {
 root /usr/share/;
 }
}
location /phpmyadmin {
 rewrite ^/* /phpMyAdmin last;
}

Подключаем конфиг в разделе server своих сайтов

/etc/nginx/conf.d/my.domain.conf

include /etc/nginx/snippets/phpMyAdmin.conf;

server {

 # . . . other code

 include /etc/nginx/snippets/phpMyAdmin.conf;
 # . . . other code

}

Проверяем и перезапускаем nginx

nginx -t
systemctl restart nginx

Можно входить

http://your_site_name.com/phpmyadmin