Place onion, garlic and 2 tablespoons evoo in the bottom of a large casserole. Cook in oven for 15 minutes while preparing the rest of the ingredients.
Meanwhile prepare chicken. Remove skin from the thighs. In a ziplock bag or bowl toss chicken with 2 tablespoons evoo, zaatar, ½ teaspoon salt and lemon juice. Mix until well coated.
Remove casserole from oven. Add rice and remaining 1 teaspoon salt and mix.
Arrange chicken over rice then pour boiling hot broth around the chicken. Cover with foil and place in preheated oven for 50 minutes to an hour until chicken is mostly cooked through and broth is absorbed by rice. Remove foil, (this is when you can add vegetables) drizzle more evoo if desired and roast for another 20 minutes until chicken is browned and rice is tender.
Serve as is or remove chicken to a plate and fluff up rice with a fork while mixing in toasted almonds and more zaatar to taste. Serve chicken with rice.