It shouldn't be too difficult to create a dummy tax return with 2017 TurboTax sufficient to prepare Form 8962. Either fully recreate your 2017 tax return in TurboTax if it's a simple tax return or instead just enter your personal information and a W-2 with an amount in box 1 equal to the modified AGI that must appear on Form 8962 line 2a. This is generally the AGI from your filed tax return, but it might require modification as indicated on Worksheet 1-1 in the instructions for Form 8962:
https://www.irs.gov/pub/irs-pdf/i8962.pdf
You can then just go through the Health Insurance section of 2017 TurboTax and complete that section normally, entering the details of your Form 1095-A. Finally, switch to forms mode, open Form 8962 and print the form.
