Cook the macaroni according to package instructions. Drain and set aside.
In a large saucepan, cook the ground beef over medium heat until browned. Drain any excess fat.
Add the taco seasoning and water according to the seasoning packet instructions. Simmer for a few minutes.
In a large bowl, combine the cooked macaroni, ground beef mixture, diced tomatoes with green chilies, milk, sour cream, and 1 1/2 cups of the shredded cheese. Mix well.
Transfer the mixture to a baking dish. Top with the remaining shredded cheese and crushed tortilla chips.
Bake in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbly.
Let it cool for a few minutes before serving. Enjoy!
Notes:
This casserole is perfect for a family dinner or a potluck. You can also add some jalapeños for extra heat.