Where do I report the nontaxable portion of military pay while deployed (BAH and BAS)?
You do not need to report the nontaxable BAH and BAS unless you are trying to itemize and using the Sales Tax deduction calculation. You would then use your LES information to add up how much you received in nontaxable BAH and BAS in 2018.
If you use the Standard Deduction or the State Tax (when you use the Itemized Deduction) you do not need to report the BAH and BAS nontaxable pay. It won't be included on your W-2. Therefore all you need to do is enter the W-2 information in TurboTax. If you were deployed in a combat zone there should be a code Q-nontaxable combat pay in box 12. Make sure you include this information when entering your W-2 to get the nontaxable combat pay calculated correctly in TurboTax.