use Data::Dumper;
my @keys = qw( this that those );

my $node='value';
$node={$_=>$node} foreach reverse @keys;

print Dumper $node;
__END__
$VAR1 = {
          'this' => {
                      'that' => {
                                  'those' => 'value'
                                }
                    }
        };