Q: family share no longer works with ipod nano

My children have an ipod nano each. I bought some new albums today on our shared family plan and they have downloaded on all our devices apart from these two nanos - which are the only two devices I actually wanted them for in the first place.

Why havent the nanos downloaded the music I've bought for them? I understand there is a new apple music system starting that doesnt support nanos (another con) but I havent downloaded that.

I want the music i bought to go on these two nanos - how do I do that?

Thanks