Preheat the oven to 350°.
Cook and drain the orzo.
Spray a 9x13 baking dish.
Add in the orzo, cans of diced tomatoes, half of the feta cheese, kalamata olives, lemon juice, oregano, and arugula and mix it all together.
Pour broth over the dish.
Set the casserole dish to the side and prep the chicken
Dice the chicken into approx. 1 inch pieces.
Toss the chicken in the spices and oil and place on top of the casserole.
Cover and bake for 1 hour.
Remove from the oven and top with the rest of the feta. Put back in the oven, uncovered, for about 5 min until it gets a little bit of a brown color to it.