Cook the rice noodles according to package instructions. Drain and set aside.

In a large skillet, heat the vegetable oil over medium heat. Add the chicken breasts and cook for about 6-7 minutes on each side, or until fully cooked. Remove from the skillet and let rest for a few minutes before slicing.

In the same skillet, add the sliced red bell pepper, shredded carrots, and green onions. Sauté for about 3-4 minutes until the vegetables are tender.

In a bowl, whisk together the peanut butter, soy sauce, honey, rice vinegar, sesame oil, minced garlic, grated ginger, and red pepper flakes (if using) until smooth.

Add the cooked noodles and sliced chicken to the skillet with the vegetables. Pour the peanut sauce over the mixture and toss to combine everything evenly.

Cook for an additional 2-3 minutes, stirring frequently, until everything is heated through.

Serve warm, garnished with chopped peanuts and cilantro.