This I'm sure is a backwards approach and probably not needed so not possible. Still I was wondering how to if possible as it should be...
Having added a driver to for example an object's location y, that comes from the location x of another object. I was able to add a driver modifier "Expanded Polynomial" and do simple multiple expression etc.
I then noted one can change the Driver from Blender's Transform Channel to a 'Single Property' which is symbolized by the SV (red+white Spring) Icon.
Then the property node of type "Node Tree" can be selected, which in turn means I can select an SV Node Tree by name from the popup list, (which defaults to NodeTree).
Remaining unset yet is the 'Path' value. I had attempted to add a simple Formula2Node there too (similar to the modifiers mentioned earlier, just to test multiplying etc).
I tried referencing the SV (Formula2Node) node's result via nodes['Formula'].result in various ways with no luck.
I do understand I can use a 'Set Property' node and don't need to use that Graph Editor (Drivers tab and 'N' inspector panel's) Drivers route/way, but I wondered if there is a way to reference the SV NodeTree nodes result values from an 'outside' place like that what it might be. (I also tried results, results.1 etc. but that didn't do anything either.)
Is there some kind of other output node or just an inspector node you'd use to potentially reference the value?
I'm sure there's a more complicated example where this is desirable but this is just a simple example for testing and asking the question.