Just watch that the kids feed well, and feed the nanny accordingly, she will need more concnetrate. But I have milking goats, so no idea about quantities for pygmies.
Are the kids male or female? If you have male kid(s), you will need to decide what to do with them. As you probably don't know the sire, i should think they would not be of any use for breeding. As they are older than 7 days you will have to get them castrated by the vet, otherwise they may become quite smelly and will have to be kept away from any females. But as wethers they will make ideal comapnions for females/sisters, if you decide to sell them.
You will need to get eartags with your herdnumber for them in due course (6months or when they leave the holding if that's earlier, but not for vet visit), double tags plus applicator/tagger. I can't give advice on which tags are particularly good/ or least worse for pigmies, but maybe there is a breedsociety. Also take advice from them re vaccinating.
Other than that, start giving them some hay/concentrate soon and think of some catchy names! Enjoy!