The nibbler is a common power tool used for cutting sheet metal, popular because it provides a much faster and less tiring alternative to hand tools.
This example from Laser Tools (part number 7693) can be conveniently powered by your equipped cordless drill.
With a lightweight aluminium body and composite handle, it is easy and comfortable to use. It has a smooth action that leaves the surrounding metal undistorted, and is suitable for both straight and tight curve cuts. Sheet steel up to 1.0mm thick can be cut with this tool, as well as stainless steel of 0.8mm thickness.