Error on when to load node?
"$ch1" contain tids.

The function "taxonomy_get_children($ch1);" retrieve all children term id and not related nid...

You can retrieve all nid linked with a term with this function taxonomy_select_nodes 

I will suppose $ch1 contain your tids in an array

foreach($ch1 as $tid){
    $nids  = taxonomy_select_nodes($tid);
    $nodes = node_load_multiple($nids);
    foreach($nodes as $node){
        $link = l($node-&gt;title, 'node/' . $node-&gt;nid)."&lt;br&gt;";
        print $link;
    }
}


I can't test this code, if it's valid tell me and i will remove this line :)