This package provides a simple way to nmap over all public/elastic IPs on an AWS account.
Install:
$ pip install aws-nmap
Usage:
$ aws-nmap -sC -sV
Alternatively you can:
$ aws ec2 describe-instances --query "Reservations[*].Instances[*].PublicIpAddress" --output=text > /tmp/publicips.txt
$ nmap -iL /tmp/publicips.txt -sC -sV
Assuming you want to look that up every time.