Cook the pasta according to package instructions until al dente, then drain and set aside.
In a large skillet, heat olive oil over medium heat.
Add the diced chicken and season with salt and pepper; cook until browned.
Remove the chicken from the skillet and set aside.
In the same skillet, add onions and garlic; sauté until translucent.
Add chopped bell pepper and cook for another 3 minutes.
Stir in the cherry tomatoes and return the chicken to the skillet.
Combine the cooked pasta with the chicken and vegetables.
Toss everything together and adjust seasoning if needed.
Serve hot, garnished with fresh basil and Parmesan cheese if desired.