Custom Content inside a Custom Component

Yes this is possible. I just want to mention a couple of things first though.

1) Is there a reason the custom content needs to be nested inside of a custom component? You can go over an explanation between the two here: Custom Content Module vs. Cusotm Component and here Styling custom components

2) You may want to consider making a note  or some sort of documentation of these type of "nested" changes you're making. It will help make any support issues that could arise in the future less confusing and more streamlined.

 <@component id="common.widget.custom-content" name="X"/> (where x is the number of the custom content module you wish to use)