Preheat your oven to 350°F (175°C).
In a large ovenproof skillet or Dutch oven, heat the olive oil over medium-high heat. Season chicken thighs with salt and pepper, then place them skin-side down in the skillet. Cook until the skin is golden and crisp, about 5-7 minutes, then flip and cook the other side for 3-4 minutes. Remove chicken and set aside.
In the same skillet, add the chopped onion and sliced red bell pepper. Sauté until the onion is translucent and the peppers have softened, about 5 minutes.
Stir in the minced garlic and cook for another minute until fragrant.
Sprinkle the paprika over the vegetables and stir to combine.
Add the rice to the skillet, stirring to coat the grains with the oil and toast slightly, about 2 minutes.
Pour in the chicken broth and bring to a simmer.
Crush the saffron threads in your fingers and sprinkle over the broth. Stir in the diced tomatoes and fresh peas.
Place the chicken thighs on top of the rice mixture, skin-side up. Transfer the skillet to the preheated oven, uncovered.
Bake for 30-35 minutes, or until the rice is tender and the chicken has reached an internal temperature of 165°F (74°C).
Remove from the oven and let it rest for 5 minutes before serving.