Preheat the oven to 350°F (175°C).

Grease a casserole dish.

Remove the chicken meat from the bone and cut it into bite-size pieces.

In a large pot, cook the bell pepper and onion in 1 cup of chicken broth until softened.

Cook the vermicelli pasta in the remaining chicken broth until al dente.

In a mixing bowl, combine the cooked chicken, cooked bell pepper and onion mixture, cooked vermicelli pasta, cream of mushroom soup, celery salt, black pepper, Worcestershire sauce, and half of the grated Cheddar cheese.

Mix until well combined.

Transfer the mixture to the greased casserole dish.

Sprinkle the remaining grated Cheddar cheese over the top of the casserole.

Bake in the preheated oven for 25 minutes, or until the cheese is melted and bubbly.

Serve hot.