Season the chicken breasts with salt and pepper on both sides. Then dredge in the breadcrumbs. Set aside.
In a large skillet set over medium heat, add the olive oil and butter. Swirl to coat the whole pan. Once the butter is melted, add the chicken breasts. Cook, turning once, until browned on both sides -- about 5 minutes per side.
Add the marinara and the diced tomatoes (with the juices) to the pan. Cover and cook for 10 minutes. Top with cheese and cover again. Cook for an additional 5 minutes to melt.
Serve with pasta.