Has Tony Stark ever implemented alien technology?

In the MCU only in one occasion. In the suits used for time travel in Avengers Endgame.

The suits themselves use several technologies in unison: they can enter the quantum realm by shrinking in size thanks to Hank Pym’s technology, and they use space-time GPS invented by Tony Stark as well as his latest nanotechnology.

Where Tony uses alien technology is in the visors of the suits, which look the same as those used by the Kree, and are also very similar to the holographic suits of the Guardians of the Galaxy.