Soak the rice noodles in warm water for about 30 minutes, or until softened. Drain and set aside.
In a large skillet or wok, heat the vegetable oil over medium-high heat. Add the sliced chicken and cook until browned and cooked through, about 5-7 minutes.
Add the minced garlic to the skillet and sauté for 1 minute until fragrant.
Push the chicken and garlic to one side of the skillet. Pour the beaten eggs into the other side and scramble until fully cooked.
Add the soaked noodles to the skillet, along with the fish sauce, sugar, lime juice, soy sauce, and chili powder (if using). Toss everything together and cook for an additional 2-3 minutes until heated through.
Stir in the bean sprouts and green onions, cooking for another minute.
Serve hot, garnished with chopped peanuts and lime wedges on the side.