1. Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Drain and set aside, reserving about 1 cup of pasta water.
2. While the pasta cooks, heat olive oil in a large skillet over medium-high heat. Add the chicken pieces, seasoning with salt and pepper, and cook until golden and cooked through, about 6-7 minutes. Remove chicken from the skillet and set aside.
3. In the same skillet, add the chopped onion and sauté until translucent and soft, about 4 minutes. Add the minced garlic and cook for another 30 seconds until fragrant.
4. Pour in the crushed tomatoes, chicken broth, oregano, basil, and red pepper flakes. Stir well and let the sauce simmer gently for about 8-10 minutes, stirring occasionally. If the sauce thickens too much, add a splash of reserved pasta water to loosen it.
5. Return the cooked chicken to the skillet and stir to combine. Adjust seasoning with salt and pepper to taste.
6. Add the drained pasta directly into the skillet with the sauce and chicken. Toss gently to coat the pasta evenly. If needed, add a little more pasta water for creaminess and to help the sauce cling to the noodles.
7. Remove the skillet from heat and sprinkle the torn mozzarella chunks over the pasta. Cover the skillet with a lid and let it sit for 2-3 minutes, allowing the cheese to melt beautifully.
8. Garnish with fresh basil leaves if you have them, and serve immediately while warm and melty.

One pro tip from my kitchen: don’t rush the simmering step. Letting the tomato sauce cook down a bit really deepens the flavor and makes the whole dish feel more homemade. It’s the kind of slow moment I cherish, especially when the kitchen isn’t caught up in the usual evening rush.