I googled it. It looks like you can grow them in a contraption filled with hay
You learn something every day on this forum! Although I got half way down this link and decided I'd rather stick to potato bags, far easier...https://boredomtherapy.com/straw-nest-potato/
I've seen the above done in permaculture circles but with banked up straw. I'd not heard them called nests before. (Or Horse Nests)
Seems like Holly is miles ahead of a lot of us! Not heard of it either, looks like a great space saver that a lot people might want to try.https://youtu.be/R833pkaDBSY
Considering you'd never heard of it, it's pretty random that you decided to try growing them like that!