First I would like to reiterate the fact I am not a chin owner but am not new to owning exotic pets. If I'm wrong then someone please say something. However I think this is fairly common knowledge.
Will it work? It depends. Some animals do fine with others and some do not. This is true of all species.
When introducing chins the younger the better because their behavior patterns are set at a young age. For adults who are used to being alone it will be to be irritating for them to adjust. Now it may be they could be better off (preferring to have a buddy) after the adjustment but it depends on the individual which is why I have seen it stated that you shouldn't get a second chinchilla for the sake of the other chinchilla.
Putting two same-sex chins in a cage is actually commonplace and usually does not cause problems. Females can live together just as well as males can live together. However I have read case studies of adult chins killing each other unexpectedly but they are few and far between in both male and female pairs. Introducing an adult to a baby is still risky as is introducing two adults. The damage they can inflict on each other can easily become fatal. I recently followed a case where a nursing baby killed its brother (which is not typical but also not unheard of). I say this to demonstrate there is a risk whenever you have two chins together no matter what age or relationship and great care must be taken to watch for signs of fighting.
You must slowly introduce them and observe their behavior. Start with their own cages side by side (at least two inches apart so they are out of reach of each other) and observe. If they can reach each other at this point it could result in serious and deadly injury to face and limbs.
Some animals can be very aggressive and territorial and take longer to become accustomed to each other. Rule of thumb is a week. Also make
double triple sure you are not accidentally pairing male and female or you get a different set of problems. If you are going to do this there are different techniques like swapping cages for a while or putting them together in a previously unoccupied cage once they are used to each other. This is because chins recognize their territory by their scent and will often attack the other for invading its own cage. There are other things you can do to help and a good method in this article:
http://www.huggablepets.com/huggablepets/addingchins.shtml
