Deductions & credits

You are correct you can only take one of those credits. 

1. To remove the WI School Property tax Continue the WI state interview  
2. "Edit" the "Credits and Taxes" section  
3. "Revisit" the "School Property Tax Credit"  
4. Blank out all the boxes there   
5. "Start/Revisit" the "Veterans and Surviving Spouses Property Tax Credit" 

If this is the first year you are claiming this credit you will need to obtain certification prior to claiming the credit.  

Here is an excerpt from the "More Information" link in the WI State interview, the "Veterans...property tax credit".   

"If you did not claim the credit for 2022, before claiming the credit for 2023 you must request certification from the Wisconsin Department of Veterans Affairs (WDVA) indicating that you qualify for the credit. Use Form WDVA 2097 (which you can find in WDVA Brochure B0106) to submit your request, along with a copy of the veteran's DD Form 214 and Veterans Administration disability award letter and, if applicable, the veteran's death certificate, a marriage certificate, and a completed copy of Form WDVA 0001 (if the veteran never previously submitted one). The WDVA 0001 and the brochure are available from your county veterans service officer or on the Internet at www.dva.state.wi.us. You may submit these forms and supporting documents to your county veterans service officer or mail them to: Wisconsin Department of Veterans Affairs, 30 West Mifflin St., PO Box 7843, Madison WI 53707-7843. If you qualify, the WDVA will send you a certification of your eligibility.

Note You do not have to obtain certification from the WDVA for 2023 if you previously received certification for 2022. If you still qualify for the credit, you may claim the credit but do not have to enclose certification."