Cook the cheese tortellini according to package instructions. Drain and set aside.
In a large skillet over medium heat, add olive oil and let it heat up.
Add the diced chicken breasts to the skillet and season with salt and pepper. Cook until the chicken is browned and cooked through, about 5-7 minutes.
Add minced garlic to the skillet and sauté for an additional 1-2 minutes, until fragrant.
Pour in the heavy cream and bring to a gentle simmer.
Stir in the basil pesto and grated Parmesan cheese, mixing until the cheese is melted and the sauce is combined.
Add the cooked tortellini and cherry tomatoes to the skillet, gently tossing everything together until the tortellini is well coated in the creamy pesto sauce.
Cook for another 2-3 minutes on low heat to heat through. Adjust seasoning with salt and pepper if necessary.
Remove from heat and garnish with fresh basil leaves before serving.