My biggest planted tank has been 1800l. Not in some ways it is more physically harder, having to get inside to aquasape it, but in others, the principles are the same.
With a big tank, you can really get stuck in and scrub around and it soon looks as if nothing has been touch, where as a nano, one leaf out of place looks colossal.
The thing with big tanks is the cost more than anything, more space means more plants, which means more lights, filters, fertilizers. Its costly, but I wouldnt say much more work, ide say its easier. Ive got from 8l to 1800l and back again, and the principles of scaping stayed the same, but the physics of getting it done had to change.
Cheers.