Heat 1 tablespoon of olive oil in a large skillet or pot over medium heat. Add the diced chicken and season with 1 teaspoon salt, 1 teaspoon Italian seasoning, and 1/2 teaspoon black pepper. Cook for about 5–6 minutes, stirring occasionally.
Add 4 cloves of minced garlic and continue cooking for another few minutes until the chicken is fully cooked through.
Transfer the chicken to a separate bowl and lightly drizzle with balsamic vinegar. Toss to coat and set aside.
Bring a large pot of salted water to a boil and cook the penne pasta according to package directions until al dente.
While the pasta cooks, add the remaining tablespoon of olive oil to the same pan used for the chicken.
Add the cherry tomatoes and season with 1/2 teaspoon salt.
Stir in the remaining 4 cloves of minced garlic and cook for about 5 minutes, or until the tomatoes become soft and lightly wilted.
Stir in 1 tablespoon balsamic vinegar and 1/2 cup chopped fresh basil.
Add the cooked chicken back into the pan.
Add the cooked pasta to the skillet and toss until everything is evenly coated.
Stir in the mozzarella pearls.
Top with additional fresh basil if desired and serve immediately.