Prep the chicken: Pat chicken dry and cut into 1-inch pieces. Season all over with 1 teaspoon salt, 1/2 teaspoon black pepper, and 1 teaspoon Italian seasoning.

Brown the chicken: Heat 1 tablespoon olive oil in a large, deep skillet over medium-high. Add chicken in a single layer. Sear 3–4 minutes per side until golden and just cooked through. Transfer to a plate; keep warm.

Sauté aromatics: Lower heat to medium. Add another tablespoon oil. Stir in garlic, sun-dried tomatoes, and red pepper flakes. Cook 60–90 seconds until fragrant, being careful not to brown the garlic.

Build the sauce base: Pour in chicken broth, scraping up any browned bits. Simmer 2–3 minutes to concentrate flavor.

Add dairy gently: Stir in half-and-half and bring to a gentle simmer. Reduce heat to medium-low. Whisk in Parmesan until smooth.

Stabilize with yogurt: Turn the heat to low. In a small bowl, whisk the Greek yogurt with a few spoonfuls of the hot sauce to temper it. Then whisk this mixture back into the pan. The yogurt adds protein and body without breaking the sauce.

Cook the tortellini: Add tortellini directly to the skillet. Stir and cover. Simmer on low 4–6 minutes (refrigerated) or 6–8 minutes (frozen), stirring once or twice, until tender and the sauce thickens. If it gets too thick, splash in more broth.

Finish with greens and chicken: Fold in the spinach and the cooked chicken with any juices. Let the spinach wilt, 1–2 minutes. Taste and adjust seasoning with salt, pepper, and extra Italian seasoning if needed.

Serve: Top with more Parmesan and chopped basil or parsley. Serve hot, straight from the skillet.