Looking good there T2D2. Looks like the same pots and tubs I have. Just curious.

What chestnut? Dunstan?

Stratify in ziplocks or containers?

What kind of soil for stratification?

What kind of potting soil in pots?

You have any chestnut trees already?

If you haven't done this before one thing to watch for is as the radical starts growing it might push itself out of the soil. Just push it back in. Common to see it lift the nut as good roots get established. Usually takes about a week or less to grow root to bottom of those pots then it usually branches and sends the trunk up. Good luck