To filter VPC Ids
aws ec2 describe-vpcs --filters Name=tag:Name,Values='dev vpc' Name=tag:ServiceName,Values=xyz --query Vpcs[].VpcId
To get public Ips for a given Vpc
aws ec2 describe-nat-gateways --filter Name=vpc-id,Values=vpc-1abc184a --query NatGateways[].NatGatewayAddresses[].PublicIp
This will give us a list of public IPs
NAT Public IPs
"X.X.X.X",