Preheat the oven to 425°F (220°C).
In a large bowl, combine the baby potatoes, carrots, red bell pepper, and red onion.
Drizzle 2 tablespoons of olive oil over the vegetables, then sprinkle with 1/2 teaspoon salt, 1/4 teaspoon black pepper, 1/2 teaspoon dried thyme, and 1/2 teaspoon dried oregano. Toss well to coat evenly.
Arrange the seasoned vegetables in a single layer on a large sheet pan.
In the same bowl, add the chicken thighs. Drizzle with the remaining 1 tablespoon olive oil.
Sprinkle the chicken with garlic powder, smoked paprika, remaining 1/2 teaspoon salt, remaining 1/4 teaspoon black pepper, remaining 1/2 teaspoon dried thyme, and remaining 1/2 teaspoon dried oregano. Rub the seasoning evenly over the chicken thighs.
Place the chicken thighs skin-side up on top of the vegetables on the sheet pan, spacing them evenly.
Roast in the preheated oven for 35 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the vegetables are tender and caramelized.
If desired, broil for an additional 2-3 minutes to crisp the chicken skin further, watching carefully to avoid burning.
Remove the sheet pan from the oven and let the chicken rest for 5 minutes.
Garnish with chopped fresh parsley before serving.