You can now create security groups in AWS Network Load Balancer (AWS NLB)
With this update, you can configure rules to ensure that your NLB only accepts traffic from trusted IP addresses, and centrally enforce access control policies
If you are using EKS just update your LB controller to 2.6.0 version and configure it🫡
Please check out more information here:
https://aws.amazon.com/about-aws/whats-new/2023/08/network-load-balancer-supports-security-groups/
https://docs.aws.amazon.com/elasticloadbalancing/latest/network/introduction.html