Heat a Dutch oven or large pot over medium heat. Once hot, add 1 tablespoon of olive oil.
Add the chicken and cook, stirring frequently, until the chicken is opaque and beginning to brown, about 5 minutes. Remove the chicken to a plate lined with paper towels and set aside.
Add the remaining tablespoon of olive oil to the pan, then add the onion and garlic. Cook, stirring frequently, for about 5 minutes.
Add the bell peppers and cook for about 5 more minutes until the onion is tender. If the pan looks dry at any point, add about a tablespoon of chicken stock.
Add the chicken stock, tomatoes, cooked chicken, basil, oregano, bay leaf, black pepper, and cayenne. Mix well, then bring everything to a boil.
Stir in the spaghetti, then lower the heat. Cover and simmer, stirring occasionally, until the spaghetti is tender, about 10 minutes.
Remove the bay leaf and stir in the parsley.