NiCd batteries are charged in very much the same way as the more modern NiMH rechargeables that are everywhere these days...so not really anything very exotic. And they may be o.k. I'm still using NiCds that are almost 20 years old.
If yours say they are 1500mAh then they should ideally be charged at 1/10 of that, so 150mA. At that rate a full charge takes about 15 hours.
Your "chargers" really supply a bit too much current but should be o.k. provided you don't leave the battery on charge for than an hour or so initially. If you have a DMM check the voltage before you start the charge and after the hour. It may be zero initially, that's o.k. but you're aiming for something around 4.2V when it's fully charged.
Steve