Report of chronicler on burial site, potentially a cracker (12)
I believe the answer is:
cryptanalyst
'a cracker' is the definition.
(a cryptanalyst cracks codes)
'report of chronicler on burial site potentially' is the wordplay.
'report of' indicates a 'sounds like' (homophone) clue.
'chronicler' becomes 'annalist' (someone who writes annals).
'on' says to put letters next to each other.
'burial site potentially' becomes 'crypt' (underground burial site).
'annalist' is a homophone of 'analyst'.
'analyst' after 'crypt' is 'CRYPTANALYST'.
(Other definitions for cryptanalyst that I've seen before include "Code breaker" , "GCHQ worker" , "Codebreaker" .)