Plain nurse’s distorted description of Iberia (10)
I believe the answer is:
peninsular
'description of iberia' is the definition.
(Iberia is a peninsula)
'plain nurse's distorted' is the wordplay.
'distorted' is an anagram indicator.
'plain'+'nurse'='plainnurse'
'plainnurse' with letters rearranged gives 'PENINSULAR'.
(Other definitions for peninsular that I've seen before include "description of a war" , "Insure plan (anag)" .)