Meanwhile, make the sauce. Heat a large skillet on medium-low heat. Add the tomato sauce and oregano, and stir to combine. Simmer until mixture thickens, about 3-5 minutes. Add salt and pepper to taste.
Once meatballs are done, transfer them to the sauce and gently toss to fully coat. Stir in the basil. Place the mozzarella cheese in the tomato sauce and over the meatballs and continue cooking on medium-low heat for an additional 5-7 minutes, or until the cheese has melted into the sauce. Serve and enjoy!