Heat neutral oil and toasted sesame oil in a large pot over medium heat. Add the chopped white parts of the green onions, minced ginger, and minced garlic. Sauté for 1-2 minutes until fragrant.

Pour in the chicken broth, soy sauce, rice vinegar, and crushed red pepper flakes (if using). Bring the mixture to a gentle boil.

Carefully add the raw chicken breasts to the boiling broth. Reduce heat to a low simmer, cover, and cook for 15-20 minutes until the chicken is cooked through (165°F internal temp).

Remove the cooked chicken from the pot and transfer to a cutting board. Let rest for a few minutes, then shred using two forks.

Return the broth to a rolling boil. Add your chosen noodles and cook according to package directions until tender.

Return the shredded chicken to the pot to warm through. Remove from heat and stir in half of the reserved green parts of the scallions. Taste and adjust seasoning if necessary.

Ladle soup into bowls. Garnish with remaining green onions, fresh cilantro, and a drizzle of chili oil if desired. Serve immediately.