In a large pot, over medium heat, combine 10 cups of water, chicken thighs, garlic, ginger, the whites of scallions, and a generous pinch of salt and pepper. Bring the mixture to a rolling boil, allow to boil for 5-7 minutes, then reduce heat and let it simmer gently for 20 minutes.

After 20 minutes, carefully remove the chicken from the broth and shred it into bite-sized pieces. Keep the broth warm.

Add dried ramen noodles and matchstick carrots to the simmering broth. Cook according to package instructions, around 4-5 minutes.

Once noodles and carrots are cooked, stir in the black rice vinegar, soy sauce, and toasted sesame oil. Simmer for an additional 2-3 minutes.

Return shredded chicken to the pot, stir to combine, and serve hot garnished with scallion greens and drizzle with crispy chili oil if desired.