Error Deploy Load Balancer

Hello.

There was also a similar report on GitHub issue.
https://github.com/aws-ia/terraform-aws-eks-blueprints/issues/1426

You probably created an IAM policy using the steps in the document below, and in that case, I think "elasticloadbalancing:AddTags" is allowed, but please check to be sure.
https://docs.aws.amazon.com/eks/latest/userguide/lbc-manifest.html

Also, as mentioned in the GitHub issue, updating to the latest version may improve the issue, so please try it.