Season the chicken thighs with salt, black pepper, and garlic powder. Let sit for a few minutes.
In a large skillet over medium-high heat, add olive oil. Sear the chicken thighs until golden brown on both sides, about 3 to 4 minutes per side. Remove from skillet.
In the same skillet, sauté chopped onion and minced garlic until soft, about 2 to 3 minutes. Add rinsed rice and ground cumin, toasting for about one minute.
Pour in chicken broth and bring to a gentle simmer. Return seared chicken to the skillet, cover, and cook on low heat for about 20 minutes.
In a blender, combine cilantro, jalapeño, garlic, lime juice, olive oil, and salt. Blend until smooth.
Plate the rice and chicken, drizzling generously with the green sauce.