Soak the rice noodles in warm water for about 15-20 minutes until they are softened. Drain and set aside.
In a bowl, mix together the tamarind paste, fish sauce (or soy sauce), brown sugar, lime juice, chili powder, and a pinch of salt. Adjust the flavors according to your taste preferences.
Preheat your air fryer to 350 degrees F (175°C), for 3-5 minutes. If using tofu or chicken, lightly sauté it in a pan with a bit of oil until cooked and slightly crispy. Set aside.
Add the sliced onions and minced garlic, to the air fryer, brush with olive oil, or spray with olive oil. Set cook time for 2-3 minutes until they are softened.
Push the onions and garlic to the side of the basket and pour the beaten eggs into the empty space. Let them cook for a minute or so, then scramble them with a spatula until they are fully cooked and mixed with the onions.
Add the soaked rice noodles to the air fryer basket. Pour the prepared sauce over the noodles. Gently toss and mix everything together using tongs or a spatula. If using pre-cooked tofu or chicken, add it now. Air fry the mixture at 350 degrees F (175°C) for 4-5 minutes, tossing or stirring occasionally to ensure even cooking.
Open the air fryer and add the bean sprouts and chopped green onions. Toss everything together again. Once the noodles are heated through and the bean sprouts have slightly softened, remove the basket from the air fryer. Serve the Pad Thai in bowls, garnished with crushed peanuts and lime wedges.