If you are eligible for the unemployment exclusion, the IRS will recalculate your federal tax return and send you a refund of the federal tax that you paid on your unemployment benefits. For the federal tax it doesn't matter what state you live in.
There is no tax break for unemployment on the Mississippi state tax return. Mississippi does not exclude part of your unemployment income from tax like the federal government does. All of your unemployment income is taxable in Mississippi. So you will not get any money back from Mississippi for your unemployment.
You do not have to amend your tax return. The IRS will recalculate your federal tax, and they do not want you to file an amended return. There is nothing to amend your state tax return for, because there is no tax break for unemployment on the Mississippi state tax return.
