Peel the carrots and julienne 2 of them. Juice the remainder.
Rinse the rice and place in a medium bowl. Sprinkle with tablespoon salt and cover with hot water. Set aside.
In a deep pan or pot, drizzle oil over medium high heat. Add onions and cook, stirring often, until softened and translucent. Add the chicken thighs and cook until golden brown. Stir in the sliced carrots and cook, stirring often, until softened, about 5 minutes. Add enough carrot juice to reach halfway up the chicken and vegetables.
Reduce heat to low, cover the pot halfway with a lid, and simmer for 30-40 minutes, stirring occasionally. Stir in the coriander, cumin seeds, and season with salt. Drain the rice and evenly spread over the chicken and vegetables. Pour in the remaining carrot juice to cover the rice and increase heat to medium high.
Once most of the juice has evaporated, reduce heat to low, stir the top of the rice, cover and cook for 15 minutes.
Remove the lid, stir the top of the rice, cover again, and cook until rice is tender, another 10-15 minutes.
Stir everything together and serve immediately.