Why isn't the onclick function working on a class?

I'm running Drupal 7 with JQuery and Node.js. I want an event to happen in a div onclick event. However, it won't work on a class, although it works if I use the parent div id.

The line that I'm having trouble with is:

    $(document).ready(function() {

  $('.chatNickname').click(function(){ 
alert("hello");
  });

The code snippet works in jsfiddle..not sure what the problem is. The entire code is below:

<script src="http://<?php print $_SERVER['SERVER_ADDR'] ?>:8080/socket.io/socket.io.js"></script>
<script>
  (function($){
    var myNick = 'me';
    var newlyJoined = true;
    var socket = io.connect('http://<?php print $_SERVER['SERVER_ADDR'] ?>:8080');

    socket.on('connect', function () {
      $('#chat').addClass('connected');
    });

    socket.on('announcement', function (msg) {
      $('#lines').append($('<p>').append($('<em>').text(msg)));
    });

    socket.on('nicknames', function (nicknames) {
    $('#nicknames').empty().append($('<span>Online: </span>'));
      for (var i in nicknames) {
    $('#nicknames').append($('<div class="chatNickname" id="' + nicknames[i] + '">').text(nicknames[i]));
      }
    });

    socket.on('user message', message);
    socket.on('reconnect', function () {
      $('#lines').remove();
      message('System', 'Reconnected to the server');
    });

    socket.on('reconnecting', function () {
      message('System', 'Attempting to re-connect to the server');
    });

    socket.on('error', function (e) {
      message('System', e ? e : 'A unknown error occurred');
    });

    socket.on('chat log', function(chatlog) {
      if (newlyJoined) {
    var i = 0;
    for (stamp in chatlog) {
      if (chatlog[stamp].type == 'user message') {
        var ts   = tstamp(stamp);
        var nick = chatlog[stamp].nick
        var msg  = chatlog[stamp].msg
        message(ts, nick, msg);
        i++;
      }
    }
    if (i > 0) {
      $('#lines').append($('<hr>')).append($('<small style="text-align:center; display:block; color: #888;">').text('Chat messages posted within the past half hour appear above this line.')).append($('<hr>'));
      $('#lines').get(0).scrollTop = 10000000;       
    }
    newlyJoined = false;
      }
    });

    function message (msg_time, from, msg) {
      $('#lines').append($('<p>').append($('<small>').text(msg_time)).append($('<b>').text(from), linkify(msg)));
    }

    function linkify(inputText) {
      //URLs starting with http://, https://, or ftp://
      var replacePattern1 = /(\b(https?|ftp):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/gim;
      var replacedText = inputText.replace(replacePattern1, '<a href="$1" target="_blank">$1</a>');

      //URLs starting with www. (without // before it, or it'd re-link the ones done above)
      var replacePattern2 = /(^|[^\/])(www\.[\S]+(\b|$))/gim;
      var replacedText = replacedText.replace(replacePattern2, '$1<a href="http://$2" target="_blank">$2</a>');

      //Change email addresses to mailto:: links
      var replacePattern3 = /(\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,6})/gim;
      var replacedText = replacedText.replace(replacePattern3, '<a href="mailto:$1">$1</a>');

      return replacedText
    }

    function tstamp(stamp) {
      var currentTime = new Date(); 
      if (typeof stamp != 'undefined') {
    currentTime.setTime(stamp);
      }
      var days = new Array('Sun', 'Mon', 'Tue', 'Wed', 'Thr', 'Fri', 'Sat');
      var day = currentTime.getDay();
      var hours = currentTime.getHours();
      var minutes = currentTime.getMinutes();
      if (minutes < 10) {
    minutes = "0" + minutes;
      }
      if (hours > 11) {
    var ap = 'p';
      }
      else {
    var ap = 'a';
      }
      if (hours > 12) {
    hours = hours - 12;
      }
      return "["+ days[day] + " " + hours + ":" + minutes + ap + "m] ";
    }

    $(document).ready(function() {

      $('#nicknames .chatNickname').click(function(){ 
    alert("hello");
      });

      $('input#message').focus(function() {
    if ($(this).val() == 'Type your chat messages here...') {
      $(this).val('');
    }
      });

      $('input#show-timestamps').click(function() {
    if ($(this).is(':checked')) {
      $('#messages p small').show();
    }
    else {
      $('#messages p small').hide();
    }
      })

      socket.emit('nickname', '<?php print $username ?>', function (nick) {
    if (nick != 'me') {
      myNick = nick;
      socket.emit('get log');          
      return $('#chat').addClass('nickname-set');
    }
      });

      $('#send-message').submit(function () {
    message(tstamp(), myNick, $('#message').val());
    socket.emit('user message', $('#message').val());
    clear();
    $('#lines').get(0).scrollTop = 10000000;
    return false;
      });

      function clear () {
    $('#message').val('').focus();
      };

    });
  })(jQuery);
</script>
<div id="chat">
  <div id="messages">
    <div id="nicknames">
    </div>
    <div id="lines">
    </div>
  </div>
  <form id="send-message" autocomplete="off">
    <input id="message" type="text" value="Type your chat messages here..." autocomplete="off" />
    <button>Send</button>
  </form>
</div>
<small><input id="show-timestamps" type="checkbox" checked="checked" /> Show timestamps</small>