E.T.
Yes, you can safely nurse. Most viruses cannot be passed through breastmilk. However, they can be passed by close contact, which a baby will have whether breastfed or not.
Otherwise, wash your hands, but in all likelihood, your child will get the cold in some form.
Should your child get sick, I have found that saline nasal spray is your best friend for baby head congestion (my pediatrician recommends it too).
Good luck.