1993 American strat here with this huge roller nut! Anyone know anything about these?
Looks like a Wilkinson.
That IS a Wilkinson roller nut.
You shouldn't lube them. Clean them with a brass wire wheel on a grinder or drill press, then a gasoline bath - but only this time as gasoline is just a tad greasy and will keep the rollers slippery. Very very finicky machines, likely to buzz on open strings and they only take 9's and 10's. But far more superior than Fender LSR ball bearing nuts.
They were often put on American Strat Plus that had modern block saddles and non-locking type of a trem with locking tuners. There was also a Strat Plus Ultra, that had an LSR nut, locking Fender trem (called a Fender Floyd as it says Floyd Rose on the baseplat, but was actually licensed) and locking tuners. The entire Plus series was equipped with Lace Sensors.
Not sure about the Wilkinson but have quite a bit of experience with the Fender LSR. Actually have one on my #1 guitar along with a Wilkinson VS100 vibrato bridge and Sperzel tuners.
If it is working properly - blow out the dust and debris with low pressure compressed air and apply a tiny drop of light machine oil on each ball with the tip of a pin or pick. If it's really gunked up, I'd recommend removal and light, carefull cleaning with a soft toothbrush dampened with Isopropyl Alcohol (generally safe on plastics and rubber and most finishes). Dry and oil as described above.
The LSR's are a little delicate and I suspect the Wilkinson's are too. Inspection with magnification before you start is highly recommended.