passar valor de input hidden via ajax

bom dia amigos,

estou tentando passar valor de um input via ajax, mas sem sucesso:

meu input:

<input type="hidden" value="<?php echo"$nick";?>" name="nick" class="nick" id="nick">

código ajax:

...

var nick = $("#nick").val();

 $('#results').load('autoload_process.php?nick='+nick, {'page':track_load}, function() {track_load++;}); //load first group

 $(window).scroll(function() { //detect page scroll

...

código completo ajax:

$(document).ready(function() {
 var track_load = 0; //total loaded record group(s)
 var loading = false; //to prevents multipal ajax loads
 var total_groups = 10; //total record group(s)
var nick = $("#nick").val();

 $('#results').load('autoload_process.php?nick='+nick, {'page':track_load}, function() {track_load++;}); //load first group

 $(window).scroll(function() { //detect page scroll

 if($(window).scrollTop() + $(window).height() == $(document).height()) //user scrolled to bottom of the page?
 {

 if(track_load <= total_groups && loading==false) //there's more data to load
 {
 loading = true; //prevent further ajax loading
 $('.animation_image').show(); //show loading image

 //load data from the server using a HTTP POST request
 $.post('autoload_process.php',{'group_no': track_load}, function(data){

 $("#results").append(data); //append received data into the element

 //hide loading image
 $('.animation_image').hide(); //hide loading image once data is received

 track_load++; //loaded group increment
 loading = false;

 }).fail(function(xhr, ajaxOptions, thrownError) { //any errors?

 alert(thrownError); //alert with HTTP error
 $('.animation_image').hide(); //hide loading image
 loading = false;

 });

 }
 }
 });
});

qual o problema que o autoload_process.php não esta recebendo o nick?

obrigada!