Add the last tablespoon of oil to the skillet and heat until hot and rippling. Add the red bell pepper and the peanuts and cook until the pepper is softened, 2 to 3 minutes. Remove the mixture into the bowl with the chicken, trying to leave as much oil as possible behind in the skillet.
Add the garlic, ginger and red pepper flakes to the remaining oil in the skillet and cook over medium heat, stirring constantly, for about 30 seconds to 1 minutes. Stir in the chicken broth. Break the bricks of ramen into small chunks and add them to the skillet. Bring the mixture to a simmer and cook, tossing the ramen constantly with tongs to separate, until ramen is just tender but there is still a bit of liquid in the pan, about 2-4 minutes.
Stir in the hoisin sauce, vinegar, and sesame oil and continue to simmer until the sauce is slightly thickened, about 1 minute. Stir in the chicken, peppers and peanuts. Sprinkle with green onions before serving. Serves 4-5.