Play’s unusual theme, describing Tesla, a nuisance (3,7)
I believe the answer is:
the tempest
'play's' is the definition.
(I've seen this before)
'unusual theme describing tesla a nuisance' is the wordplay.
'unusual' is an anagram indicator.
'describing' indicates putting letters inside (describe can mean to form the outline of).
'tesla' becomes 'T' (scientific unit).
'a nuisance' becomes 'pest' (I've seen this before).
'theme' with letters rearranged gives 'hetem'.
'hetem' enclosing 't' is 'thetem'.
'thetem'+'pest'='THE TEMPEST'
(Other definitions for the tempest that I've seen before include "Here observe Miranda" , "Prospero, Miranda play" , "Shakespeare play" .)