There is no chill on HNSS.. There is no "chill" either. Stock is trading and HNSS does not show up on any DTC ineligible lists.
Just because your specific brokerage decided to not let you sell a certain security does not mean the stock is chilled. It is a direct issue with your broker.
I have called BOTH my brokerages and BOTH have said HNSS is not under any trading restrictions.