Preheat the oven to 350°F (175°C).
Heat olive oil in a large skillet over medium heat.
Add diced onion and cook for 3-4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook until browned, breaking it apart with a spoon, about 6-8 minutes.
Drain excess fat from the skillet.
Stir in diced tomatoes with juice, tomato sauce, dried Italian seasoning, salt, and black pepper.
Add frozen mixed vegetables and simmer for 5 minutes, stirring occasionally.
Remove skillet from heat and stir in cooked elbow macaroni until well combined.
Transfer the mixture to a 9×13 inch baking dish and spread evenly.
Sprinkle shredded cheddar cheese and mozzarella cheese evenly over the top.
Bake uncovered in the preheated oven for 20 minutes, or until the cheese is melted and bubbly.
Remove from oven and let cool for 5 minutes before serving.