How to configure SSL Certificate on K8s Cluster with 10 Nginx Pods and Load-Balancer?

I am working on a project to build a kubernetes Cluster with 6 droplets including three K8s nodes and three Mongodb nodes. The frontend service has 10 Nginx Pods running on two nodes and a load-balancer forwards traffic to Nginx Service’s NodePort. So far, everything works fine. Now I am trying to add the support of HTTPS traffic with SSL Certificate. My questions are how do I configure Commercial SSL Certificate on the frontend? Should I set up the SSL on load-balancer or 10 Nginx pods ? Which one is the better choice and how to do it ? Should I buy Commercial SSL Certificate or use free Let’s Encrypt ?

Any suggestions or help would be gratefully appreciated.

Thanks in advance, Michael