Become crazy nationalist instead of good migrant (5)
I believe the answer is:
nomad
'migrant' is the definition.
(someone who travels around)
'become crazy nationalist instead of good' is the wordplay.
I cannot quite see how this works, but
'crazy' could be 'mad' (synonyms) and 'mad' is found within the answer.
'nationalist' could be 'n' (abbreviation in politics) and 'n' is found in the answer.
'of' could be 'o' and 'o' is found in the answer.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
(Other definitions for nomad that I've seen before include "Wanderer" , "Member of travelling people" , "Itinerant" , "One keeps moving" , "drifter" .)