In a large, deep skillet or Dutch oven, heat olive oil over medium-high heat. Add the diced chicken, season with salt, pepper, and Italian seasoning. Cook for 5–6 minutes until the chicken is golden and mostly cooked through.
Add the minced garlic and cook for 1 minute until fragrant. Pour in the marinara sauce and chicken broth, stirring to combine.
Stir in the uncooked pasta, making sure it's mostly submerged in the liquid. Bring the mixture to a boil, then reduce heat to low. Cover and simmer for about 12–14 minutes, stirring occasionally, until the pasta is tender and the liquid has mostly absorbed.
Once the pasta is cooked, remove the skillet from heat. Sprinkle mozzarella and Parmesan cheese over the top, then cover the pot for 2–3 minutes to let the cheese melt. For an extra cheesy top, broil briefly if your skillet is oven-safe.
Top with fresh basil or parsley and a pinch of red pepper flakes, if desired. Serve warm and enjoy!