Not related to Ephraim Chubbuck or Abigail Nye so can't help you on death date for Abigail Nye but believe you have the wrong parents listed for her.
The Abigail Nye who married Ephraim Chubbuck was from Wareham, MA who was born on 12 Feb. 1775 at Wareham, MA to David and Desire Nye. See Wareham birth list at
http://www.warehamhistory.com/WarehamGenWeb/BD.htm . For Wareham marriage record of their marriage see
http://www.warehamhistory.com/WarehamGenWeb/WrhmVR.htm .
Hope this helps. Regards, Bill.