In Blender, AI or Moho I can select nodes by proximity or connection on a path by a key plus a click (and hence copy-paste as new shape to another layer).
How to do this in Inkscape?

Only way by now is trying to select them by click-drag but this appear cumbersome and unprecise.

Kind regards, Raaskot

Select one or more shapes and switch to the node tool. Place your pointer over a node and use [mouse_wheel] to select and deselect adjacent nodes. [ctrl+mouse_wheel] restricts node selection to the current subpath. You can move the pointer to another node to add and remove nodes from the selection.

I'm not sure I understand. Copy+Paste nodes works inside compound paths or as new object already. To select nodes just select 1 an go Select All and you have all continuous nodes selected - for instance.