Figure out the female and separate them. Although the male won't necessarily kill the baby they will continue to breed, in fact the female may be bred again already as they can breed back immediately after birth. Since you don't know if these chins are related, any of their backgrounds, etc. it would not be ideal to continue to allow them to breed.
Make sure that the mom and baby are in a cage with small wiring that the baby can not get out of. Keep her with lots of fresh hay, clean water, and pellets and make sure they baby's belly feels round, this indicates that they are getting plenty of milk.
The male and female will probably call to each other, and the male may even shake the bars of the cage wanting out, or pace. This is not because they love and miss each other so much, it's the equivalent of a hormonal teenager in the middle of a swimsuit contest... his only desire to be back with the female is to continue the species.