For laser cutting you’ll need curves. Take your surfaces and type _DupBorder.
If you want to automate nesting parts for lasercutting, I recommend the OpenNest plugin. If you do this on a regular it will save you a lot of time.
Grasshopper OpenNest is working as expected, although baking the curves generates an error on invalid object and some aren’t closed.
There is something going on with your curves. If you create a bunch of rectangles OpenNest will do it’s thing using the Rhino Command Line. Converting your curves to line (Convert) and SimplifyCrv gets them nesting.