1. **Marinate the Chicken**: In a large mixing bowl, combine the Greek yogurt, lemon juice, minced garlic, grated ginger, ground coriander, ground cumin, paprika, ground turmeric, cayenne pepper, garam masala, salt, and black pepper. Add the chicken thighs to the marinade, ensuring they are well-coated. Cover the bowl and refrigerate for at least 1 hour, preferably overnight for enhanced flavor.

2. **Sear the Chicken**: Heat 1 tablespoon of olive oil or coconut oil in a large, deep skillet or Dutch oven over medium-high heat. Remove the chicken thighs from the marinade, allowing any excess to drip off, and sear them in the skillet for about 3-4 minutes on each side, until browned. The chicken does not need to be fully cooked at this stage. Transfer the seared chicken to a plate and set aside.

3. **Prepare the Rice**: In the same skillet, add the chopped onion and green bell pepper. Sauté for 2-3 minutes until the onion becomes translucent. Add the ground turmeric, ground cumin, and ground coriander, stirring to combine with the vegetables. Add the rinsed basmati rice to the skillet, stirring to coat the rice with the spices and oil. Cook for 1-2 minutes to toast the rice slightly.

4. **Cook the Rice and Chicken Together**: Pour in the chicken stock, scraping up any browned bits from the bottom of the skillet. Season with salt and black pepper. Bring the mixture to a gentle boil. Return the seared chicken thighs to the skillet, nestling them into the rice. Reduce the heat to low, cover the skillet with a lid, and let it simmer for 20-25 minutes, or until the rice is tender and the chicken is cooked through.

5. **Serve**: Remove the skillet from heat and let it sit, covered, for 5 minutes. Fluff the rice with a fork and serve the Tandoori Chicken over the rice. Garnish with fresh cilantro leaves and lemon wedges, if desired. A side of mint yogurt sauce can also complement the dish well.