Season the chicken breasts with salt, black pepper, paprika, and cayenne pepper.
Heat olive oil in a large pan over medium heat. Add the chicken and cook for 5-6 minutes on each side until golden brown and fully cooked.
Remove the chicken from the pan, let it rest for a few minutes, then slice it into thin strips.
Bring a large pot of salted water to a boil and cook the pasta according to the package instructions until al dente. Drain and set aside.
In the same pan used for the chicken, melt the butter over medium heat.
Add the minced garlic and chopped onion, sautéing for 2 minutes until fragrant.
Stir in the sliced jalapenos and cook for another minute.
Pour in the heavy cream and milk, stirring continuously.
Gradually add the Parmesan cheese, allowing it to melt into a smooth, creamy consistency.
Season with Italian seasoning, red pepper flakes (if using), salt, and black pepper.
Add the cooked pasta to the sauce and toss until evenly coated.
Stir in the sliced chicken and let it warm for another minute.
Serve hot, garnished with extra Parmesan and jalapeno slices for an extra kick.