[IKRM]

If I have a region and under the region a topic is it possible to create a sub topic under the topic?

IKRM

[andy]

I've never heard of  a topic having a sub topic. That is an SMF support question. It is best to ask there.
http://www.simplemachines.org/community/index.php

You can make a category with sub categories, or put a topic in that.

Unless you are talking about the use of blocks or simple portal articles? Sorry, it is hard to understand what you want.

Simple Portal articles have categories but not sub categories. But you could create category 1 (add topic as article), then add category 2 with sub topic article.

If it is a block with a topic link and under that a sub topic link, you can do that with a simple html block. It would be static - wont change if your board topics change.