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 baking 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 nicely seared but not cooked through.
Place the browned chicken on top of the vegetable and bean mixture in the baking dish; brush the chicken with a little additional balsamic vinegar.
Pour 1 1/2 cups chicken broth into the dish around the chicken and scatter the chopped oregano over the top.
Bake in the preheated oven 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 hot chicken and vegetables, and allow the cheese to soften for a few minutes before serving.
Serve the chicken and vegetable mixture on its own or over rice or pasta if desired.