Deductions & credits

You can enter your prior year unused foreign tax carryovers using the online version of TurboTax in the Foreign Taxes section, which in under Estimates and Other Taxes Paid. You must indicate that you have foreign taxes paid in the current year on the screen that says Foreign Tax Credit:

On the screen that says No Other Income or Expenses answer "no" and you will prompt the program to generate Form 1116. Later, you will be asked to pick the country the foreign tax was paid in, so enter the country but leave the income and tax amount either blank or enter $0. 

Eventually, you will come to a screen that says Foreign Tax Credit Carryovers where you can enter your carryover numbers: