Splitting a hive.
I use 10 frame boxes with slots cut in the inside of the front and back that I slide that plastic election sign stuff in so I can drop frames in as they grow without disrupting them. Can't use screen bottom boards or slat racks with them though.
Yeah you can, build your own like I did.
As for other uses for a nuc:
1. Small hive cut outs.
2. Overwinter OB Hive.
3. Walk away splits.
4. Queen bank, cut a groove centered on each end (inside) for sliding a queen 2 frames of worker bees. When you need to requeen just pull the 2 frames and insert into hive that needs the queen.
5. Raising Queens, a combination of #3 & 4 above.