Are you referring to paying your federal taxes or TurboTax Fees? For your federal tax payment, you won't be able to split the payment using two different cards through Turbotax. However, you can use the IRS payment site to make two separate payments. To make your payment on the IRS website, please see the below link. In TurboTax, you will want to select "Pay by check" during the filing process. It will include a 1040-V (Payment Voucher) which you can disregard to make your payment online.
IRS Pay Online
If you are referring to your TurboTax fees then your payment option is limited to one credit card. For more information, please see the below TurboTax help article.
How can I pay my TurboTax Online fees?