Colorado Tabor Tax

You can file an amendment after your original tax return is fully processed.  Wait until the state processes your return, as they may include it without you having to do anything.   If they don't adjust for it, come back and file the amendment.   If you do end up having to file the CO amendment, you can add the credit by taking the steps below.   

It is at the end of the state interview, after income, taxes, and credits.   You have to answer 2 questions before the credit shows up.  

1. Were you incarcerated?  NO
2. Will you file your return on time?  YES

Once you answer both of those, the credit ($480) will appear on line 35 of your CO tax return (Form 104).   See below.

If your tax return gets rejected, you can add the credit before you re-submit it.   But if your return has been accepted, you will need to wait until that return is processed.