A large nonstick skillet's flat surface allows for more of the food to come in direct contact with the high heat, which ensures the food browns more evenly and efficiently.
But if you’re using a skillet, aren’t you just sautéing? No, because proper ingredient prep and staggered cooking also come into play.
Even a skillet set over high heat won’t get hot enough to quickly stir-fry either large amounts or large pieces of food. So it’s important to cut the ingredients into bite-size pieces and to cook relatively small amounts of food at one time. And because stir-fries cook so fast, it’s essential to have all your ingredients prepped—also known as mise en place—before you start cooking.