Ajax function not returning any html
Got it. I returned the answer with ajax_deliver :

function mij_add_aide_list_proposition($nodes){
    // Magic stuff goes here (construction of $nodeList)
    $build['content'][]=array(
      '#prefix'=&gt;'',
      '#suffix'=&gt;'',
      '#markup'=&gt;$nodeList,
    );

  //$test=drupal_render($build);
  ajax_deliver($build);
}


If someone finds another way, I'm open to any change !