Which one is correct?
Anthing you say isn't going to change a thing.
Anthing you do isn't going to change a thing.

or

Nothing you will say is going to change a thing.
Nothing you will do is going to change a thing.

Question

Which one is correct?
Anthing you say isn't going to change a thing.
Anthing you do isn't going to change a thing.

or

Nothing you will say is going to change a thing.
Nothing you will do is going to change a thing.

Answer

Even though "anything" (not "anthing") and "nothing" mean different things, both forms of this sentence are OK. You could also say "Nothing that you say...".