The way of cutting sheets with nibbler is to cut punches out of a tiny metal sheet and repeat the process until you get your desired dimension.
How to manually cut letering out of sheet metal.
Another tool is a plate shear for cutting slightly.
How to plasma cut calligraphy letters.
One tool is a foot shear or a jump shear.
I have seen a few metal cutting tools such as snips and nibblers but they cut through the metal to get to their point of interest which i only want the lettering to be cut.
I have also read that laser water cutting nozzles can get caught in stamped grooves which could damage the nozzles so that option is out.
There are three tools that kevin caron uses a lot to get a precise cut from a thin piece of metal.