Borg nanites prior to First Contact and "Scorpion"

Are there any references, either in the official canon or in the Extended Universe, to Borg nanites and/or nanoprobes prior to First Contact and the Voyager two-parter "Scorpion"?

During TNG, the Borg are only seen to assimilate individuals "manually", that is, by having drones add implants and components to the exterior of an individual's body. (I am mainly referring to Picard's assimilation in "The Best of Both Worlds".)

In First Contact, we see nanoprobes in use, but we also see Borg drones adding some components (e.g. cybernetic forearms) to mostly-assimilated individuals. It can be deduced from this that nanites can achieve a basic, common standard of assimilation (including cybernetic organelles) while specialized external hardware must be added manually.

Is there any evidence that TNG writers conceived of nanoprobe-based assimilation before First Contact? Alternatively, did the idea arise in the Extended Universe before being made canon in First Contact and being further refined in Voyager?