The number one rule of getting chicks to use a poultry nipple drinker is to TAKE ALL OTHER WATER OUT. If they aren't thirsty, they won't use it especially if their other drinker is there. I've given a nipple drinker to day old chicks with no other options and they picked it up on their own. I like to give them a few days with a cup, though. I assume the nipple is made out of red plastic? Chickens are instinctively attracted to red. If you're worried, here's a stress free way to transition them.
1) Install nipple drinker
2) REMOVE OTHER WATER SOURCE from morning until night. This will stimulate their thinking. Chickens are very smart given the chance.
3) Put their old drinker in at night and let them get a good long drink to ease your mind. (note that this makes the process take longer, but if it makes you feel better it's okay)
4) In the morning, remove their other drinker again. Leave it out allllllllllll day like before.
5) Put it back in that night / remove the next morning.
6) Repeat for approximately 3 days......but after that don't let them have their bowl drinker anymore.
For adult birds, just take the water bowl out, put the nipple drinker in,.............Done. They won't let themselves dehydrate. (assuming normal weather temperatures, of course. Don't transition fast in a major heat wave)