Blissful state (7)
'blissful state' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nirvana that I've seen before include "Buddhist 23" , "Kurt Cobain's grunge band" , "Transcendent state of Buddhists" , "Ultimate state in Buddhism" , "State of pure happiness" .)
(Other definitions for ecstasy that I've seen before include "Powerful hallucinatory drug" , "State of euphoria or dangerous drug" , "Intense happiness" , "Feeling of immense rapture" , "State of bliss or euphoria" .)