Marinate the chicken in a Ziploc bag with the lemon juice, oregano, coriander, chopped garlic, and olive oil. Season with salt and pepper. Marinate for no longer than 4 hours. When ready grill on medium-high heat till cooked through, about 4 minutes per side.
In a saucepan melt the butter over medium heat then add the spices and cook until fragrant. Add the rice and stir to coat. Cook about 4 minutes until rice is slightly toasted. Add chicken broth, bring to a boil, cover reduce to a simmer, and cook for 15 minutes without disturbing. Remove from heat and rest 10 minutes without opening the lid.
In a small bowl combine yogurt, Sriracha to taste, and garlic. Let sit in fridge.
To assemble place chicken on rice and top with sauce. Enjoy!