Hi, and welcome to DC
There's no reason you can't use turkey thighs in a stir-fry, or cooked in any number of ways. Just make sure the meat is cooked through. The most accurate way to do that is to get an instant-read thermometer.
For stir-fry, cut the meat into bite-size pieces about the same size as the other ingredients in your dish (I go for about 1"x1" squares or cubes). Stir-fry the meat, remove it to a plate, stir-fry the veggies, add sauce ingredients, stir till thickened, then add the meat back and heat through. This should cook it sufficiently.