You don't say if these goats are recently weaned kids or adults. If they are kids, they are missing the familiarity of their former home and possibly their moms and other herd members.
If they are adults, they too are making the adjustment from leaving their former herd.
In either case, time will correct the situation. You have to bite the bullet and ride this out until they adjust to your farm. Kids would take the longer time to make the adjustment.
Nubians are know to be more vocal that other breeds of goats...at least mine are.
I have 3 and they are the loudest out of all my goats. The only that has saved me was giving them a nice big hay feeder full of hay at all times (free choice). That way they have something to munch on and occupy their mouths. 
If you ignore them I promise they will settle in and be quiet. The only time mine cry now is if they hear the back door close or the back gate open. They know that means someone is around and just might give them something. 
They might be missing their herd mates but they will soon realize they are a herd of 2 now and be ok. Try not to go check on them every time they cry or they will have you trained and will cry even more.
