This isn't nolens volens, but it is at least a second cousin:

willy-nilly

Function: adverb or adjective
Etymology: alteration of will I nill I or will ye nill ye or will he nill he
1 : by compulsion : without choice


(I don't include the 'spontaneous' definition #2 on purpose here because that's not a second cousin.)

unwillingness

Here are two very good words for that state: nolleity and nolition (n.).

willingness

Then there are velleity: just a wish to do something

And volition: a stronger, active determination to do something than mere velleity


So, nolens is like nolleity/nolition...

And volens is like velleity/volition...

And we can pounce the cat and have our nolleity velleity and nolition volition, I suppose.