In a large bowl, combine the chicken thighs, salt, black pepper, garlic powder, onion powder, paprika, and cayenne pepper (if using). Mix well to coat the chicken evenly with the spices.
Heat the olive oil in a large skillet over medium-high heat. Add the seasoned chicken thighs and cook for about 5-7 minutes on each side, or until browned and cooked through. Remove the chicken from the skillet and set aside.
In the same skillet, add the chopped onion and bell pepper. Sauté for about 3-4 minutes until softened. Add the minced garlic and cook for an additional 1 minute until fragrant.
Pour in the diced tomatoes (with their juice), chicken broth, and Worcestershire sauce. Stir to combine and bring to a simmer.
Return the chicken to the skillet, cover, and let it simmer for 15-20 minutes, allowing the flavors to meld together.
Once cooked, garnish with fresh parsley before serving.