Is it good to do a BBA from an open university run by a state government like KSOU and TNOU to get in a better college in the future for studying an MBA?

Joining an MBA college does not usually depend on a student graduating with a regular course or correspondence course. But if you are not from a regular course, you tend to miss a lot of experiences which are only possible in a college atmosphere. 

During your interview for admission in an MBA course, you will be asked why you opted for this rather than a regular college. You might have to put some more focus on extracurriculars as they will also come in handy during your selection.

Your selection will only be considered if there are not many students from regular courses applying for MBA. It is a very rare situation, and you should not depend on it.

It is suggested that you go for correspondence BBA or any graduate course. Join the full-time program and get familiar with the classroom environment. Symbiosis or Manipal is recommended for BBA as they are more reputed colleges than state Universities.