In a large pot of salted water, cook the pasta according to package instructions. Drain the pasta and set aside.
In a small bowl, combine all the seasonings.
Beat the chicken breasts until even in thickness. Season both sides of each chicken breast.
Add oil to a large skillet and heat over medium-high heat. Once hot, add the chicken breast to the pan.
Sear the chicken on both sides until golden brown. Turn the heat down to low, cover the pan, and cook until the chicken reaches 165°F internal temperature.
Remove the chicken from the pan and set aside.
Add butter and diced onion to the same skillet; saute on medium heat until softened.
Add the minced garlic and cook until fragrant.
Add the marinara sauce to the skillet and bring it to a simmer.
Slice the chicken into thin strands and add to the marinara sauce. Add ¾ cup of mozzarella, parmesan cheese, and pasta; stir to combine.
Top with the remaining mozzarella cheese. Cover the skillet with the lid and cook until the cheese melts.
Serve and enjoy, friends!