Step 1

Preheat oven to 375 degrees F. Generously spray a 9x13-inch casserole dish with cooking spray.

Step 2

In a large skillet, heat olive oil, then add chicken and diced onion. Cook over medium-high heat until chicken is cooked through and begins to brown, stirring frequently to keep onions from burning. Season to taste with salt and pepper

Step 3

Transfer chicken and onions to prepared casserole dish. Set aside.

Step 4

In a large mixing bowl, combine stuffing mix, half (1 c.) of the shredded cheese, canned tomatoes, half (1/8 c.) of the balsamic vinaigrette, minced garlic, and Italian seasoning. Mix well until thoroughly combined.

Step 5

Spread the stuffing mixture evenly over the chicken into the prepared baking dish.

Step 6

Top with the remaining mozzarella cheese.

Step 7

Bake casserole in preheated oven, uncovered, for 35 minutes until the cheese is melted and the sauce is bubbly.

Step 8

Remove from oven, cover with foil, and allow the dish to rest for 5 minutes before serving.

Step 9

Garnish with chopped basil leaves and a drizzle of the remaining balsamic vinaigrette.