FTFY, you need to pass $_ to full_name so it knows what subcountry you want to look up.

use strict;
use warnings;
use Data::Dumper;
use Locale::SubCountry;

    my $country = new Locale::SubCountry('United States');
    my @states  = $country->all_codes;
    my @list;
    my %state_hash = $country->code_full_name_hash;
    our $subcountry = do {
        @list = map { { code => uc($_), name => $country->full_name($_
+) }}
+ @states;
    };
print Dumper(\@list);
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