Preheat oven to 375 and spread one jar of pasta sauce into the bottom of a 9x13 baking dish.
Top with 1/2 cup parmesan cheese and mix sauce well.
Add chicken breast to the sauce and dredge in sauce to coat both sides of the chicken. Make sure the chicken is a single layer.
Cover the casserole dish with foil and bake for 30 minutes.
While the chicken is cooking, bring a large pot of water to a boil. Add spaghetti and cook according to package directions. Reserve 1 cup of water before draining and keeping pasta warm.
Remove chicken parmesan from the oven, and remove aluminum foil.
Sprinkle top of the chicken with shredded mozzarella cheese and top with an additional 2 tbsp. Grated parmesan. Return the dish to the oven for 10 minutes or until the cheese is melted.
Toss cooked pasta with reserved water and top with chicken.
Drizzle with sauce from the pan. Serve Chicken Parm topped with chopped fresh parsley if desired.
Notes
Use leftover chicken and pasta sauce between toasted bread for a delicious sandwich. This also makes an easy weeknight meal that is also a simple recipe. Store leftovers in an airtight container in the fridge and use the microwave to warm them. Skip the pasta noodles and use zoodles made from zucchini or spiralized spaghetti squash.