I really don't imagine so. Even if you could, you could buy 100 replacement tips before you recovered the cost of the equipment needed.
The only equipment needed would be a bench power supply, some scrap steel, and some sort of chemical solution. The DIYer will have the first two items, but maybe the third is a problem...
Toilet cleaner grade HCL + iron nails and you got your electrolyte.
Why would you want to do that? Tips aren't that expensive and the good brands last long enough that DIY replating doesn't really make sense. If you're tips only last an unnaturally short time, then clearly something is wrong.
It might make sense if you have an exotic iron (obtained used for a tiny fraction of the original price, of course) like a Metcal that only works with expensive tips. Or it might make sense if you're making special tips for a soldering gun. Solid copper wire can make all sorts of unusually shaped tips for a soldering gun, but bare copper erodes away too fast.
Quality electroplating is much more than just having metal ions collect onto a surface. Getting excellent adhesion of the plated metal to the substrate is not trivial or easy. Add the difficult environment of a soldering iron tip with materials with different thermal coeficients of expansion and repeated aggressive thermal cycling that incur heavy shear stresses at the plating/base metal interface. Good luck with DIY on this.
Back on topic, I know this will start a major firestorm but here goes. For the last aprox 35 years I have always had a tin of Nocorrode brand zinc chloride paste flux right next to my soldering irons. If my tip is not bright I do a quick dip in the flux and then wipe on the wet sponge. Instant perfectly tinned tip all the time. I probably do 10 or 15 joints between dips. I NEVER put that flux directly on the parts I am soldering, only to clean the tip and then a sponge wipe. I use traditonal rosin based electronic fluxes for any directly applied fluxing. I have not noticed any substantial decrease in tip life and my tips always look like new. I still have things around soldered with this method that are 35+ years old (a Heathkit decade box) no evidence of abnormal corrosion. I don't think any functional amount of zinc chloride gets to the solder joint. I completely understand that if you dipped a stranded wire in the zinc chloride flux and then solder it in a joint you are asking for major trouble. The flux will wick up the strands and start destroying things in short order. DONT USE ZINC CHLORIDE FLUX FOR ELECTRONIC FLUXING. I realize that for meeting many specs this procedure would be competely forbidden.
Let the torrent of abusive comments begin.
I am using Stannol Tippy activator/re-tinner for "tired" tips. Does wonders.