You cannot tile on top of stucco, without first removing the stucco. Stucco is not strong enough to bond tile too.

If it’s true three coat cement stucco I don’t see a problem. If it’s ‘stucco’ over styrofoam it sounds iffy.

I just googled it, since I thought maybe that had changed through the years. Nope, google says, not a good idea. https://ctasc.com/expert-answers/can-i-adhere-tile-to-a-stucco-wall/

Thanks for the advice, won’t try it.