01 - Bring a large pot of salted water to a rolling boil. Add the tortellini and cook according to package directions until they float and are tender. Drain through a colander and set aside.
02 - While the pasta cooks, heat olive oil and butter together in a large skillet over medium-high heat. Add the chicken pieces, season generously with salt, pepper, and Italian herbs if using. Cook undisturbed for 3–4 minutes per side until golden brown and cooked through to 165°F. Transfer the chicken to a plate and tent loosely with foil.
03 - Reduce the heat to medium. In the same skillet with the rendered drippings, add the chopped onion and cook until softened and translucent, about 3 minutes. Stir in the minced garlic and sauté until fragrant, about 30 seconds, being careful not to let it brown.
04 - Pour in the heavy cream and add the cream cheese and grated Parmesan. Stir continuously and bring to a gentle simmer. Continue cooking until the cheeses have fully melted and the sauce is smooth and velvety, about 2–3 minutes.
05 - Add the chopped spinach to the sauce, folding it in gently. Cook just until the leaves are wilted and bright green, about 1–2 minutes. Do not overcook.
06 - Return the seared chicken and cooked tortellini to the skillet. Toss everything together gently until evenly coated in the creamy sauce. Taste and adjust seasoning with additional salt and pepper as needed. Serve immediately, garnished with extra Parmesan and fresh parsley if desired.