Can we Just use Nginx to complete the VRA loadbalance ？
Sure, but there are no official guides to walk you through the process.
I have got an error :'Could not connect to remote host lb.rt.lab at port 443. Host name is invalid or certificate is not installed correctly on the server.' when configuring the VRA with Nginx lb
Are you doing SSL passthrough on the LB?
Per Alex's post above, sounds like you don't have the LB hostname as a subject alternate name in your certificates.
I have a simple knowledge to Nginx ,but Should I configure loadbalancer as follow the paper"Instanllation and configuration" ?