If you use shelled chestnut, it will have a less fresh and sweet taste. I highly suggest using the chestnut with shell, because it is more aromatic and sweet.
Use small chestnut is better than a large one. Because small chestnut needs less cooking time, so it preserves the original taste and favor.
Add less salt in this dish. Sweet and aromatic chestnut is the main taste of this dish. Only use salt for seasoning, if you like the strong taste, you can add chicken powder instead.