Ya, this would likely be about the hardest tank possible to maintain. Not impossible but would require a ton of work growing and cultivating their food on a constant basis.
Nudi are all very specialized feeders and they can not be trained to eat other foods. You have to provide the one thing they eat, or they die. Berghias are pretty much the easiest nudi to keep, since we know that they exclusively eat apstasia, which is pretty common in all our tanks. But they are voracious eaters and will eat themselves out of food rather quickly.
To keep them long term you need another tank that is dedicated to growing and propagating these pest anemones. You will also need to regularly remove many of the Berghia to try and balance the amount of food needed for the size of the colony because they can quickly explode in numbers, and then over populate. People will buy Berghias from you if you do this which could be beneficial but they are a lot of work to maintain long term which is why you rarely see anyone, even professionals, that have been able to maintain a consistent healthy colony for more then a year or so.
Likewise there are some you see occasionally in the hobby that eat sponges. We all have a fair amount of sponge in our tanks but even a single nudi could eat through all the sponge in my 500g tank in only a few months (I even grow chalice sponge which is a fairly fast growing sponge) and once they deplete that supply you will need to buy a bunch more on a regular basis (which would get very costly, very fast)
Either way Nudi are certainly one of my favorite sea creatures, I wish they were easier to keep, since they come in such a variety of shapes, colors and sizes. They are really amazing, but keeping them long term in a tank is no easy task, even for seasoned professionals, so I would recommend to just admire them from a far