Sure, just make sure you copy all your .tax2018 datafile(s) on a USB stick from the MAC, and put them on your PC's hard drive. The normal place the 2019 software will look for them (ot the 2018 software if you install that on the PC too), is in the PC's TurboTax sub-folder in the Documents folder.
If you think you will be shutting down and trashing the MAC anytime soon, make sure you get copies of every PDF file for each year you used the MAC. You won't be able to use any datafiles before 2016, so the PDFs will be critical. 2016, 2017, and 2018 software can still be installed on your PC, but none of the prior years.....and next Nov....2016 will go away...(every year, one more year is dropped)