Works for me on Perl v5.8.5, Linux 2.6.9, Getopt::Long INST_VERSION 2.36, even when using strict and warnings:

$ cat 641306.pl
use strict;
use warnings;
use Getopt::Long;
my @chk;
GetOptions('nodelist=i{4}' => \@chk);
print "@chk \n";
$ perl 641306.pl --nodelist 1 2 3 4
1 2 3 4
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What's you version of Getopt::Long?