Group of workers covered by nation’s laws (8)
I believe the answer is:
statutes
'laws' is the definition.
(I know this)
'group of workers covered by nation's' is the wordplay.
'group of workers' becomes 'TU' (Trade Union).
'covered by' means one lot of letters goes inside another.
'nation's' becomes 'state's' ('state' can be a synonym of 'nation').
'tu' going inside 'states' is 'STATUTES'.
(Other definitions for statutes that I've seen before include "Legislative acts" , "orders" , "Official and written laws" , "Laws passed by legislation" , "Attest us under written laws" .)