I am a Canadian living in the US. I retired in 2023 and returned to Canada mid year how do I file my taxes.

Were you a US Resident or Non Resident Alien?

If you were a US resident, then you would include the income earned while a Resident on the US return.  After you returned to Canada, if you no longer have US source income, you would not need to file a return.  If you do have US source income, that income would then be reported on a 1040NR which TurboTax does not support.  However, you could use Sprintax.com to file the 1040NR.