How to create a certificate with full chain

You will probably receive two cert files from your Certification authority (i.e. NameCheap or COMODO SSL):
yourdomain_com.ca-bundle and yourdomain_com.crt

Let's combine the two files with the following command:

cat yourdomain_com.crt yourdomain_com.ca-bundle > motion_combine.crt

Let's move the combined .crt inside the proper folder:

mv motion_combine.crt /etc/pki/tls/certs/motion.crt

Finally, please restart nginx service and Asterisk to apply your changes:

service nginx restart
service asterisk restart