Mix together balsamic vinegar, 1/2 tablespoon of olive oil, white sugar, and water.
Combine marinade with chicken pieces in a plastic bag and marinate for 1 hour.
Add 1/2 tablespoon of olive oil to skillet and saute chicken for about 10 minutes.
Chop chicken into 1/2-inch cubed pieces.
Set aside.
In a large bowl, add tomatoes, cucumber, scallions, mozzarella cubes and olives to the bowl.
Place the basil and lemon juice in a small bowl and slowly add the remaining olive oil, mixing with a fork.
Season with salt and pepper.
Add the chopped chicken cubes.
Pour the dressing over the salad and toss until combined.
Serve.