You will not be able to claim any tax credit for US withholding taxes on stock held in your TFSA.

U.S. stocks held in a TFSA are subject to a 15 percent withholding tax on dividends.

All Canadian investments held in a TFSA are not taxed when withdrawn, nor are the gains made on these investments taxed. However, this does not apply to U.S. stocks held in a TFSA.