Prepare the Sauce:
In a small bowl, whisk together fish sauce, brown sugar, soy sauce, rice vinegar, lime juice, tamarind paste (if using), and chili flakes. Set aside.
Cook the Noodles:
Boil rice noodles according to package instructions. Drain and rinse under cold water to prevent sticking. Set aside.
Cook the Chicken:
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.
Add the sliced chicken and cook until browned and fully cooked (about 5-7 minutes). Remove from the skillet and set aside.
Make the Pad Thai:
Add the remaining oil to the skillet. Sauté the minced garlic for about 30 seconds.
Push the garlic to one side and pour in the beaten eggs. Scramble the eggs until just set.
Add the cooked chicken back to the skillet, followed by the noodles and sauce. Toss everything together until well combined and heated through.
Stir in the bean sprouts and green onions.
Serve:
Transfer the Pad Thai to plates or bowls.
Garnish with chopped peanuts and lime wedges. Serve immediately.