Heat olive oil in a large skillet over medium-high heat.
Season chicken thighs with salt and pepper.
Brown the chicken thighs in the skillet for about 5 minutes on each side.
Remove chicken and set aside on a plate.
Add chopped onion and sliced bell pepper to the skillet; sauté until softened.
Stir in minced garlic and cook for 1 minute until fragrant.
Add diced tomatoes and chicken broth to the skillet, stirring to combine.
Return the chicken to the skillet, skin side up.
Sprinkle oregano over the chicken and sauce.
Cover and simmer for 30 minutes, until chicken is cooked through.
Garnish with fresh parsley before serving.