I received a 1099 MISC income, and it includes withholding, plus accompanying 592-b for withholding of taxes in another state (non_resident). Where do I enter the 592b?

You can enter both Federal and State withholding that is not shown on a reporting form:

• Open (continue) your return in TurboTax Online. (If your return isn't open, you'll need to sign in, click Take me to my return, then click Pick up where I left off.)
• Click My Account (top right of your screen).
• Select Tools.
• In the pop-up window, select Topic Search.
• In the search bar, type estimated.
• In the results box, highlight estimated tax paid, then click GO.
• You'll land on the Estimates and Other Income Taxes page. 
• Scroll down to Other Income Taxes Paid in 2016 and click Start next to Withholding not already entered on a W-2 or 1099. 
• You'll be able to include Other Withholding Not Already Entered, in your case, local income tax.