Have a look at: https://debugger.na0.netsuite.com/app/help/helpcenter.nl?fid=section_4337905245.html See the option.source part. Also, what you want to do is form.addField({id: 'custpage_test_id', type: serverWidget.FieldType.SELECT, label: 'MyList', source: 'custlist123'}); // Where custlist123 is the internalId of your custom list you want to source in the field. And form is your nlobj form object.