Hi John C3, thank you for attending the event and post a question.
Yes, you are correct that you need to have tax liability in order to utilize the electric vehicle credit (form 8936). This is a nonrefundable credit, part of Form 1040, Schedule 3 Additional Credits and Payments, line 6f.
Converting some of your Traditional IRA into a Roth IRA is a taxable event and you can use the tax credit to offset any potential tax due.
Attached is the Form 1040, Schedule 3, form 8936 draft forms for your reference.
https://www.irs.gov/pub/irs-dft/f1040--dft.pdf
https://www.irs.gov/pub/irs-dft/f1040s3--dft.pdf
https://www.irs.gov/pub/irs-pdf/f8936.pdf
Hope this helps. Thank you.