As far as I know you can`t create a node from a node that’s in the node bin directly. You would have to save the node setup, create the node, and then load the saved node setup into the node you created.
Doesn’t it take longer to use a contextual menu selection than to drag a node from a bin?
I gues you’d get the benefit of precise placement in the schematic, node naming, automatic links etc.
If you’re just simply looking to create a script for a node there’s a script on the portal called Batch Nodes that will let you either select and flame node and add it to a right click menu or you can right-click on a node and create a menu from that and it will save whatever settings you have. So you could just drag your PaintCH node into batch, right-click and save a menu. Then you should be able to assign it to a button on your stream deck.