Export PFX with crt and key

openssl pkcs12 -export -out domain.com.pfx -inkey domain.com.key -in domain.com.crt

Export PEM with p7p

openssl pkcs7 -print_certs -in domain.com.p7b -out domain.com.pem

install certficate on NGINX

your server /etc/nginx/nginx.conf file in SSL block

 listen       443 ssl;

        server_name  domain.com;

        root /usr/local/www/;

        index index.php index.html index.htm;

        ssl_certificate      /usr/local/etc/nginx/ssl/domain.com.pem;

        ssl_certificate_key  /usr/local/etc/nginx/ssl/domain.com.key;

        ssl_session_cache    shared:SSL:1m;

        ssl_session_timeout  5m;