Start a large pot of salted water boiling and cook the penne according to package directions until al dente. Reserve ½ cup of pasta water before draining.

While the pasta cooks, season chicken pieces generously with salt, pepper, and paprika. Heat olive oil in a large skillet over medium-high heat until it shimmers. Add chicken pieces in a single layer, avoiding overcrowding. Let them sear undisturbed for 3-4 minutes until golden brown, then flip and cook another 3-4 minutes until cooked through to 165°F.

Remove chicken to a plate and reduce heat to medium. In the same skillet, add diced onion and bell pepper. Cook for 3-4 minutes until softened and fragrant. Add minced garlic and cook for another 30 seconds until aromatic.

Pour in diced tomatoes with their juice, chicken broth, and Italian seasoning. Let this simmer for 3-4 minutes, allowing the flavors to meld. Slowly stir in heavy cream. Return the cooked chicken to the skillet.

Add the drained pasta directly to the skillet along with half the mozzarella cheese. Toss everything together, adding reserved pasta water if needed to achieve a silky consistency. Taste and adjust seasoning with salt and pepper.