You will have passed on immunity prior to birth (if you have had them) and will also pass on immunity in your milk. It is unusual for a child under one to get chicken pox. If they do then it's usually a very mild version. This is what the Dr told me when my DS was exposed to chicken pox aged 3
Dc2 & 3 got chickenpox when dc4 was a week old. Dc4 got about 5 spots on her face - one was huge! That was it. I was bf her. HV said was possible she would get chickenpox again as she hadn't really had it properly.
I have 2 friends who both have toddlers & newborns who got chicken pox. One newborn was ok, just got the pox and poor mum had a rough couple of weeks. The other got the pox but also developed pnemonia and had a couple of days in hospital. So just be aware that it can happen (both were breastfed too).