And with very few changes you can make it an lvalue, so you can use it to assign to:

sub nested : lvalue {
  @_ == 1
   ? $_[0]
   : nested($_[0]{$_[1]}, @_[2..$#_]);
}
[download]

..and now you can say:

TThis can lead to such fun looking constructs as nested $hashref, a => b => c => d => = 42; Note that this code will only work under perl 5.6.0 or later, though; earlier perls had more restricted definitions of lvalues. See also descending a tree of hash references.

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'