Place the chicken in a medium container. Rub the chicken with olive oil, garlic powder, onion powder, ground black pepper, paprika powder, dried thyme, dried oregano, Italian seasoning, and salt. Marinate the chicken in the fridge for at least 10 minutes.
Arrange chicken thighs on prepared baking sheet (spray with cooking spray).
Bake the chicken in the preheated oven at 350°F for about 30 minutes. Pull the baking pan from the oven and add mixed bell pepper with seasoning.
Put the baking pan back in the oven. Cook until the skin is crispy and the meat fully cooked (about 20-30 minutes). Note: thermometer should read 165°F when inserted near the bone.