That depends on the chicken.
The first flock I taught took a couple weeks, but I did it very slowly because it was midsummer with very hot temperatures.
The others learned from the adults who knew how and were drinking from the nipples within a few days or a week.
If you use their beaks to...
This is why I only use plastic waterers.
Too many pieces of galvanized equipment are cheap with coating that's too thin. My first waterer was galvanized and rusted in only a year. :(