[eluser]erik.brannstrom[/eluser]
All you have to do in your controller is what you've already done, namely calling nonce().
One thing that occurs to me is that you are using a config file to set the rules, which I haven't done myself. As far as I know, you can only set validation rules using config if you haven't already used the set_rules method (which is done in the nonce method). Seems a bit weird, but perhaps if you just try to move your validation rules to the controller?
And just to be sure, you are using the new form_open function to create your form, right?