In a large pot of boiling salted water, cook the penne pasta according to package instructions until al dente. Drain and set aside, reserving about 1 cup of pasta water.
In a large skillet, heat the olive oil over medium-high heat. Season the diced chicken with salt and pepper, then add it to the skillet. Sauté for about 5-7 minutes, or until the chicken is cooked through and golden brown. Remove the chicken from the skillet and set aside.
In the same skillet, add the minced garlic and red chili flakes. Sauté for about 30 seconds until fragrant, being careful not to burn the garlic.
Add the crushed tomatoes and tomato paste to the skillet. Stir in the sugar to balance the acidity, and season with salt and pepper to taste. Bring the sauce to a simmer and let it cook for about 10 minutes, stirring occasionally.
Return the cooked chicken to the skillet, then add the drained pasta. Toss well to combine, adding reserved pasta water a little at a time until desired sauce consistency is achieved (it should be slightly creamy and well-coated).
Plate the pasta, topping with fresh basil leaves and a generous sprinkle of grated Parmesan cheese.
Notes
Adjust the red chili flakes to your spice preference.