Bring 12 cups water to a boil in a large pot. Stir in macaroni. Stirring occasionally, cook until tender, about 7 minutes.
Meanwhile, place squash in a large, wide, microwave-safe bowl. Add 2 tbsp water, cover, and cook until very soft, about 10 minutes. Drain excess liquid. If needed, re-cover to keep warm.
Drain pasta and return to the pot. Add cheese sauce mix, milk, and butter. Mix well.
Add cooked squash to the pot and stir thoroughly. Enjoy!