Season the chicken: Season chicken with salt, pepper, and garlic powder.
Sear the chicken: Heat sesame oil and olive oil in a skillet over medium-high heat. Sear chicken 4–5 minutes per side until golden and cooked through. Remove and slice.
Build the broth: In a large pot, sauté garlic and ginger for 30 seconds. Whisk in miso paste, then pour in chicken broth, soy sauce, and rice vinegar. Simmer 10 minutes.
Cook noodles: Cook ramen noodles according to package instructions. Drain.
Add vegetables: Add mushrooms, spinach (or bok choy), and corn to broth. Simmer 2–3 minutes until tender.
Assemble & serve: Divide noodles into bowls. Ladle broth and veggies over noodles. Top with sliced chicken, egg halves, green onions, and sesame seeds.