In places, twisted part of fourth raw nugget (6)

I believe the answer is:
thrawn
'in places twisted part' is the definition.
I can't tell whether this definition defines the answer.
'of fourth raw nugget' is the wordplay.
'of' indicates the answer is hidden within the clue.
'THRAWN' can be found hidden inside 'fourth raw nugget'.
Can you help me to learn more?
(Other definitions for thrawn that I've seen before include "crooked up north?" , "perverse for a Scot" , "stubborn" .)
