In the insert pot of the Instant Pot, add the ground beef and onions. Use the saute function to brown the beef and cook the onions. Turn off saute function and drain grease if necessary. Add water, bouillon cube, tomato sauce, diced tomatoes, Italian seasoning, chili powder, bay leaves, seasoned salt, pepper, and macaroni. Stir to combine. Place the lid on the Instant Pot and set the vent to the "sealed" position. Using the manual setting, select a 5 minute cook time. After cook time is complete, allow a 10 minute natural pressure release followed by a quick release. Once the valve has dropped, open lid and carefully remove bay leaves. Stir in shredded mozzarella cheese until melted. Serve, topping with additional shredded cheese if desired (I used Colby Jack cheese for topping).