In a small bowl, mix together the Italian seasoning, garlic powder, onion powder and salt. Pat the chicken dry with paper towels, then rub the seasoning evenly over both sides of each slice.
Heat a large skillet over medium-high heat with a drizzle of oil. Add the seasoned chicken and sear for 2 to 3 minutes per side, until fully cooked through. Transfer the chicken to a plate and set aside.
Make the sauce:
In the same skillet, melt the butter over medium heat. Add the onion and garlic. Sauté for about 1 to 2 minutes until fragrant and softened.
Add the cherry tomatoes and sun-dried tomatoes to the pan along with the tomato sauce. Reduce heat to medium-low and cook, stirring occasionally, for 3 to 5 minutes, gently pressing down on about half of the cherry tomatoes with a wooden spoon to release their juices while leaving some whole for texture.
Pour in the heavy cream. Stir until combined, then add the Parmesan cheese. Stir until the cheese melts into the sauce. Season with the Italian seasoning, salt, and freshly cracked black pepper, adjusting to taste, as needed. Let the sauce simmer for 2 to 3 minutes until slightly thickened.
Add the tortellini to the sauce and toss to coat. Cook for 3 to 4 minutes so the pasta absorbs the flavors. Nestle the cooked chicken back into the skillet, spooning sauce over the top. Let everything heat through for another 3 to 5 minutes.
Garnish and serve:
Just before serving, stir in the chopped fresh basil for a burst of freshness. Plate the pasta and chicken together, spoon over extra sauce, and garnish with more Parmesan, if desired.
Notes
Storage: Store leftover chicken tortellini in an airtight container in the fridge for up to 3 days. Reheat in a skillet on the stovetop or in the microwave.