Cook the penne in a large saucepan of lightly salted boiling water for 10–12 minutes until tender. Drain and keep warm.
Meanwhile, heat the oil in a large heavy-based frying pan and cook the chicken over a high heat for 8–10 minutes until golden and cooked through. Add the pine nuts and cook for a further 2 minutes until golden. Add the cherry tomato halves and toss and cook for a further 2 minutes.
Add the drained pasta to the pan and toss well, then stir in the chopped basil and season well with pepper.
Turn into a serving bowl and stir in the mozzarella balls.