Is there's any legal way to add another set of name such as AKA or Alias?

Traditionally, in most states, one was allowed to go by any name as
long as there was no intent to deceive.  I said most states, since you
are asking about a specific state, and that state has very harsh laws
about anyone doing anything which even smells like legal advice (the
Texas Bar even sued Parson's Technology for its law program telling
how to make wills in Texas) I suspect this question should go to a
Texas attorney.

Also, with the anti-terrorist Federal Laws in action, this might not
be a good time to mess around with your official identity without
legal advice.

Likewise, do be aware of the "with no intent to deceive". If you have
some idea of getting away with something by changing your name on the
sly, that would be an intent to deceive, which is a crime in most
states.

I assume you are not talking about going to court for a legal name
change, since your question implied that was not your desire.

"Bubba" and "scooter" are taken in Texas.  There's no registry, but I
think Pancho is available again, since Waylon died, and Willie doesn't
sing that song anymore.