Step 1

Whisk together rice vinegar, fish sauce, lime juice, palm sugar, red pepper flakes, and black pepper in a large bowl.

Step 2

Marinate chicken into rice vinegar mixture; set aside while preparing remaining ingredients.

Step 3

Separate rice noodles in warm water, about 5 minutes; drain.

Step 4

Heat the vegetable oil in a large skillet or wok over medium heat. Cook and stir the garlic and onion in the hot oil until the onion is soft and translucent, about 5 minutes.

Step 5

Increase heat to medium-high. Stir chicken and marinade into onion mixture; cook and stir until chicken is no longer pink in the center and sauce begins to thicken, 7 to 10 minutes.

Step 6

Stir rice noodles, oyster sauce, soy sauce, red bell pepper, tomatoes, green onion, and basil leaves into the chicken mixture; cook and stir until sauce is evenly distributed and noodles are tender, 5 minutes more.