Mix the herbs, paprika, onion powder, garlic powder, salt, and pepper. Reserve 1 teaspoon before seasoning the chicken with the rest. Rinse and drain the rice.
Heat the olive oil over medium-high heat. Sear the thighs for about 3 minutes per side until golden, working in batches as needed, then remove.
Cook the chopped onion in the same pot over medium heat for 3–5 minutes until soft. Melt in the butter, add the drained rice, and stir for 1–2 minutes.
Add the stock and reserved seasoning, scraping the bottom. Place the chicken on top, bring to a simmer, cover, and cook on low for about 20–25 minutes, until the rice is tender and the chicken reaches 165°F away from the bone. Add water as needed if the pot dries; if the rice finishes first, remove it and finish the chicken with a little liquid.
Rest covered off the heat for 3 minutes. Fluff the rice, garnish with green onions, and divide the six thighs and rice into four servings.