Cook the Pasta
Bring a large pot of salted water to a boil. Cook pasta until al dente. Reserve ¼ cup pasta water, then drain.
Cook the Chicken
Heat olive oil in a large skillet over medium-high heat. Season chicken with salt, pepper, paprika, and Italian seasoning. Cook until golden and cooked through. Remove and set aside.
Build the Sauce
In the same skillet, sauté onion until softened. Add garlic and cook until fragrant. Stir in marinara sauce and simmer for 5 minutes.
Combine
Add cooked pasta and chicken back to the skillet. Toss to coat, adding pasta water if needed.
Add Mozzarella
Reduce heat to low, sprinkle mozzarella over the pasta, cover, and let melt.
Serve
Garnish and serve hot.