Working config:
map "$cookie_1:$arg_arg1" $new_var {
default "new";
"~:.*$" $arg_arg1;
"~*^.*:$" $cookie_1;
}
map "$cookie_1:$arg_arg1" $new_var {
default "new";
"~:.*$" $arg_arg1;
"~*^.*:$" $cookie_1;
}