Sprinkle both sides of the chicken fillets with seasoning salt, onion powder, and paprika.

Heat olive oil and butter in a large skillet over medium heat. Add the chicken fillets and cook for about 5 minutes per side, until golden brown and cooked through. Transfer to a plate and cover with foil.

In the same skillet, add minced garlic and chopped onion. Cook for 2 minutes, until fragrant.

Pour in the white wine, scraping up any browned bits from the bottom of the pan. Simmer for 2 minutes. Stir in salt, pepper, Italian seasoning, and tomato paste. Cook for 1 minute, stirring constantly.

Add chicken stock, cherry tomatoes, and crushed tomatoes. Bring to a boil, then reduce heat and simmer for 5 minutes. Taste and adjust seasoning as needed.

Return the chicken to the skillet into the tomato mixture. Sprinkle with fresh basil, mozzarella pieces, black pepper, and Parmesan. Simmer for another 5 minutes, until the chicken is heated through, the sauce is flavorful, and the mozzarella has melted.