To enter your Form 1099-INT in your amended return, please follow the instruction listed in the TurboTax FAQ below:
Please be aware that Form 1040X will not be available to prepare in TurboTax until mid-February, but once it is available, you will be able to prepare and print your amended return so that you can mail it to the IRS. Also keep in mind that you will not be able to e-file an amended return as it cannot be filed electronically. The form is only filed on paper, so it will need to be printed and filed by mail.
Please see the following TurboTax FAQ for instructions on how to amend your 2016 tax return in TurboTax: