Preheat oven to 350°F (180°C).

Boil egg noodles until tender; drain well.

In a skillet, cook ground beef and chopped onions until the beef is browned.

Drain any excess fat from the skillet.

Stir in tomato sauce and spaghetti sauce mix into the beef mixture.

Simmer until the sauce has thickened, about 5 minutes.

In a separate saucepan, combine cream cheese and evaporated milk.

Cook over low heat, stirring constantly, until the mixture is smooth and creamy.

Stir the cooked noodles and garlic salt into the cream cheese mixture.

Grease a 9-inch square baking dish.

Pour the noodle mixture into the prepared baking dish.

Spread the meat sauce mixture evenly over the noodles.

Top with shredded mozzarella cheese.

Bake in the preheated oven for 20 minutes, or until the casserole is bubbly and the cheese is melted and lightly browned.