I know in the TES universe, magic is not an inner power, but it comes from the sun and the stars which are portals to Aetherius and magic leaks out of them which gives mortals the ability to use magic.

Now that I got that out of the way, is it possible for the TES universe to have some sort of Ki/Chi energy that resides in all mortals?

Thu'um? Unless you want to classify that as another form of Aetherial magic.

If we're considering Thu'um, I might as well throw out Sword-Singing as well.