Yes you can use 2019 earned income instead of 2020 income to compute the child tax credit.
To do this in TurboTax:
- In Search, type earned income credit,
- Click Jump to earned income credit,
- Answer the questions until you reach Do you want to use last year’s earned income?
- Click Yes and enter your 2019 Earned Income.
If your earned income was higher in 2019 than in 2020, you may get a higher EITC credit by using 2019 earned income. Try it both ways in TurboTax and see what works best for you.
For more information see Earned Income Credit.