Arrange chicken thighs on a lined baking sheet and season well with salt and pepper. Cook chicken 5 inches under the broiler for 5 minutes. Open oven, slide chicken out and flip each piece over. Brush with teriyaki sauce and return to the oven for 3 minutes. Flip chicken once more, brush with sauce and return to oven for 3 more minutes or until cooked through and the sauce is bubbly and charred. Set aside.
In a large stock pot, heat oil over medium high heat and saute mushrooms with the carrot, garlic and salt until tender-- about 5 minutes. Pour chicken broth into pot followed by the Sriracha, soy sauce. Season to taste with the soy and Sriracha. Bring to a boil.
Add zucchini and ramen to the broth and cook 10 minutes or until the noodles and zucchini are tender. Remove from heat.
Slice cooked chicken and serve on top hot ramen and broth. Garnish with green onions if desired.