Preheat your oven to 350F. Spray a 3-quart baking dish with cooking spray.

Combine the broth, onion, garlic, oregano, kosher salt and pepper in a medium saucepot. Bring to a boil over medium-high heat. Reduce heat to medium and simmer for 10 minutes letting the onion and garlic begin to soften.

Meanwhile, combine the chicken pieces, orzo, 1 cup tomatoes, olives and capers in the prepared baking dish.

Pour the hot broth mixture into the baking dish and stir to combine.

Cover and bake for 45 minutes.

Uncover, stir in the arugula, Boursin and remaining 1 cup tomatoes and return to the oven, uncovered, for an additional 5 minutes until heated through.