1
You can do with original
. No need of setting nation_id
def render_change_form(self, request, context, *args, **kwargs):
if context.get('original'): #
obj = context['original']
#this will be the object you are trying to update
return super(NationAdmin, self).render_change_form(request, context, *args, **kwargs)
Source:stackexchange.com