In a large pot, heat the vegetable oil over medium-high heat. Add the chicken pieces, season with salt and pepper, and cook until browned, about 5-7 minutes. Remove the chicken and set aside.
In the same pot, add the minced garlic and grated ginger. Sauté for about 1 minute until fragrant.
Pour in the chicken broth, soy sauce, sriracha, and miso paste. Stir until the miso is dissolved. Bring the mixture to a boil.
Add the ramen noodles to the pot and cook according to package instructions, usually about 3-4 minutes.
In the last minute of cooking, add the cooked chicken and baby spinach to the pot. Stir until the spinach is wilted.
Serve the ramen hot, topped with sliced green onions, soft-boiled eggs, and a sprinkle of sesame seeds.