Hey, @Kishore, try something like this:
- hosts: localhost
  tasks:
    - name: Add each EC2 instance to the ELB
      ec2_elb:
        state: present
        ec2_elbs: load-balancer
        region: us-west-1
        instance_id: "{{ item.id }}"
      with_items: "{{ ec2_instances.tagged_instances }}"