Your system call is wrong. You're telling Perl to pass '2>nul' and '1>nul' as parameters to chcp while they only make sense in a command passed to the shell. The call should be

system('chcp 65001 2>nul 1>nul')
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which is short for

system(cmd => ( '/c' => 'chcp 65001 2>nul 1>nul' ) )
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If you want to avoid calling the shell, you need the following:

open(my $fh, '>', 'nul') or die "open nul: $!\n";
my $pid = open3(
    undef,             # Use parent's STDIN
    '>&'.fileno($fh),  # STDOUT = nul
    undef,             # STDERR = STDOUT
    chcp => 65001,
);
waitpid($pid, 0);
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Now, system is buggy on Windows, so your code might actually function as you intend it to. But if it does, you're relying on a bug in Perl.