TT has already implemented this.  Just enter your full 1099-G in Federal > Wages and Income > Unemployment Comp, and the program will take it from there.  (And it's a deduction, not a credit.)

Are you sure it wasn't your Taxes Due that were "wiped out'?

Did you already file?  That is not possible it wiped out your refund.  

Turbo Tax has been updated for the exclusion and will give it to you automatically if you qualify. If your modified AGI is $150,000 or more, you can’t exclude any unemployment compensation. Just enter the 1099G. The exclusion will be on Schedule 1 Line 8 as a negative number. Your unemployment compensation will be on Line 7 of Schedule 1. The result flows to Form 1040 Line 8.

If you have filed. The IRS will recalculate your return for the new unemployment exemption for you. There is no need for taxpayers to file an amended return unless the calculations make the taxpayer newly eligible for additional federal credits and deductions not already included on the original tax return.
https://www.irs.gov/newsroom/irs-to-recalculate-taxes-on-unemployment-benefits-refunds-to-start-in-m...