You can change nmap permissions to +s to enable setuid. Then if you want to process the text returned from nmap you can execute it like this:

my $cmd = "/usr/bin/nmap -sU -p 2300,6500 $ENV{'REMOTE_ADDR'}";

open NMAP, "$cmd|" or die $!;

foreach (<NMAP>) {
    # process here ...
}
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Hope this helps :)

Update: I think you can have security issues by enabling setuid root to nmap. Be careful. :)