Cook the tortellini according to package instructions.
Marinate the chicken breasts with olive oil, salt, and pepper.
Preheat the grill or a grill pan over medium-high heat.
Grill the chicken for 6-8 minutes per side, until the internal temperature reaches 165°F.
Remove the grilled chicken and let it rest for a few minutes before slicing.
In a large bowl, combine cooked tortellini, pesto, and cherry tomatoes.
Slice the grilled chicken and place it on top of the tortellini mixture.
Garnish with fresh basil and sprinkle with Parmesan cheese if desired.