After you file

No, it doesn't seem you need to amend your 2021 tax return, it seems you reported your spouse's basis on her 2021 Form 8606 ($6,000). 

If you entered your spouse's nondeductible traditional IRA contribution with the steps below on your 2021 tax return then you reported your spouse's basis on your 2021 tax return correctly. Since she didn't convert the money in 2021 she will have the basis on line 14 of her 2021 Form 8606 to carry to 2022. 

1. Login to your TurboTax Account 
2. Click on "Search" on the top right and type “IRA contributions” 
3. Click on “Jump to IRA contributions"
4. Select “traditional IRA” for your spouse
5. Answer “No” to “Is This a Repayment of a Retirement Distribution?”
6. Enter the amount your spouse contributed for 2021
7. Answer “No” to the recharacterized question on the “Did You Change Your Mind?” screen
8. Answer the next questions until you get to “Any Nondeductible Contributions to Your IRA?” and select “Yes” if you had a nondeductible contribution before this tax year.
9. Enter your  basis in the Traditional IRA from your 2020 Form 8606 line 14 (if you had a basis in the prior year)
10. On the “Choose Not to Deduct IRA Contributions” screen choose “Yes, make part of my IRA contribution nondeductible” and enter the amount (if you have a retirement plan at work and are over the income limit it will be nondeductible automatically and you only get a warning and then a screen saying $0 is deductible).

To enter her conversion on your 2022 tax return:

1. Click on "Search" on the top right and type “1099-R”  
2. Click on “Jump to 1099-R”
3. Click "Continue" and enter the information from your spouse's 1099-R (make sure you select that it is her Form 1099-R)
4. Answer questions until you get to “Tell us if you moved the money through a rollover or conversion” and choose “I converted some or all of it to a Roth IRA”
5. On the "Review your 1099-R info" screen click "Continue"
6. Answer "yes" to "Any nondeductible Contributions to your IRA?" since your spouse had any nondeductible contributions in prior years.
7. Answer the questions about your spouse's basis from line 14 of your spouse's 2021 Form 8606 and the value of all traditional, SEP, and SIMPLE IRAs