Bottomland
This year has been very different for germination. I collect mine and ship them everywhere. I had lower germination rates but nothing like 4 out of 30. I do stick chestnuts that show no radicle into growing media after 90 days and I see most of them come on and germinate.
Possible causes - I wish I could put my finger on it but I am sitting here scratching my head. Of the 26 that didn't germinate, I would give them the squeeze test - between the thumb and fingers. If they are super soft, throw them away. If they are white from mold, I would throw them away. The others - I would soak them for 14 to 16 hours, dry them immediately and then put them into a growing pot with moisture and put heat on them. You can't do that outside without protecting them or the critters will smell them and raid them.
My method in the previous paragraph will get 1 in 6 to 1 in 4 to germinate. Some chestnuts are super slow to germinate - it is what it is.
Killers of chestnuts are many - poor pots, wet potting soil, poor stratification are a few of them.
This is my third year with chestnuts and I enjoy them. I get reminder repeatedly - Nature is in Charge!!!!
Wayne