Season the chicken: Pat chicken dry and season with 1 tsp salt and 1/2 tsp black pepper. This helps the pieces brown and stay juicy.
Sear the chicken: Heat olive oil in a large deep skillet or Dutch oven over medium-high.
Add chicken in a single layer. Cook 4–6 minutes, stirring once or twice, until lightly browned and mostly cooked through. Transfer to a bowl and keep the pan on the heat.
Sauté aromatics: Add onion to the pan with a pinch of salt.
Cook 3–4 minutes until translucent. Stir in garlic, Italian seasoning, smoked paprika, and red pepper flakes. Cook 30–60 seconds until fragrant.
Build the base: Pour in chicken broth and crushed tomatoes.
Scrape the pan bottom to release browned bits. Bring to a strong simmer.
Add pasta and simmer: Stir in pasta and return chicken (plus any juices) to the pot. Reduce heat to medium and simmer uncovered 10–12 minutes, stirring every 2–3 minutes to prevent sticking.
Add small splashes of broth if the liquid reduces too quickly.
Add greens and optional beans: When pasta is just shy of al dente, fold in spinach and white beans if using. Cook 1–2 minutes until spinach wilts.
Creamy finish: Lower heat to low. In a small bowl, whisk Greek yogurt with a few spoonfuls of hot cooking liquid to temper it.
Stir the tempered yogurt into the pot along with Parmesan and lemon juice. Mix gently until creamy. Do not boil after adding yogurt.
Taste and adjust: Season with more salt, pepper, or lemon as needed.
If it looks too thick, add a splash of broth. If too loose, simmer 1–2 minutes more.
Serve: Top with fresh herbs and extra Parmesan. Serve hot.