The Minnesota child and family tax credit was incorrectly given to a single person with no dependants. How do I correct that to 0 before submitting the tax return?

You may be eligible for the Minnesota Working Family Credit, even without dependents.  It's a refundable credit designed for working individuals whose income is below a certain level, similar to the federal Earned Income Tax Credit (EITC).  See Working Family Credit. 

According to the instructions for Schedule M1CWFC, Minnesota Child and Working Family Credits, which can be found at Minnesota Tax Forms: 

The Working Family Credit is four percent of your first $8,750 of earned income plus an additional amount for up to three qualifying older children. See Schedule M1DQC to determine who is a qualifying older child. 

For 2023, the maximum working family credit is: 

• $350 with zero qualifying older children 

• $1,275 with one qualifying older child 

• $2,450 with two qualifying older children 

• $2,850 with three or more qualifying older children

You don't need to do anything to claim this Minnesota credit.  It's based on information that you've already included in the federal portion of TurboTax.