The nested tab is an aggregation of channels, so it is created as a JSPTableContainerProvider.
Login to the Portal Server administration console as administrator (amadmin).
Click the Portals tab and click on My Portal in the list of portals.
In the drop down list for Current Location select Enterprise Sample.
Click the Manage Containers & Channels link.
In the left side frame, select ASCTabContainer/MyTabContainer in the View Type drop down list.
In the right side frame, Click on New Tab to launch the tab creation wizard.
In the pop up wizard window, do the following.
Ensure that the values selected for Portal and DN are correct and click Next.
Specify the properties for the new tab. The Tab Name property value has to be unique across all containers. Leave the Removable property as selected, and click Next.
Ensure that the {Parent Tab Container value is set to ASCTabContainer/MyTabContainer. Select the appropriate radio button for Would you like to add content to the new tab? and click Next.
If you opted to add content to the new tab, select channels to be displayed on the tab from the list of channels. Multiple channels (e.g., SampleXML) can be selected. Ensure that the Visible on Users Desktop option is selected.
Verify that you have entered the correct information and click Next.
Click Finish.