Place the chicken in a shallow dish or resealable bag and pour 1/2 cup balsamic vinegar over it; marinate at least 30 minutes.
Preheat the oven to 400°F (200°C).
In a 9x13-inch casserole dish combine the drained white beans, cashews, whole cherry tomatoes, drained marinated artichoke hearts, and thinly sliced red onion; spread into an even layer.
Season both sides of the marinated chicken with salt and pepper.
Heat 1 tablespoon olive oil in a large skillet over medium-high heat and brown the chicken 2 minutes per side until golden (chicken will not be cooked through).
Nestle the browned chicken on top of the vegetables and beans in the casserole dish, brush the chicken with a little more balsamic vinegar, then pour 1 1/2 cups chicken broth around (not over) the chicken and scatter the chopped oregano over the dish.
Bake uncovered for 15–20 minutes, or until the chicken is cooked through (internal temperature 165°F/74°C).
Remove the dish from the oven, sprinkle the mozzarella pearls over the top, and let sit a few minutes to soften before serving.
Serve warm on its own or over rice or pasta if desired.