Well architar welcome to the world of nylon strings. If you're like me I think you'll find yourself drawn more and more to it. I almost find the metallic drone on some steel strings annoying now. Go figure.
You will have choices in the future and yet some in aspects of most classical guitars you will be limited. You may find the lack of radiused fret boards, fret makers and truss rods inexplicable. These are features you take for granted in the steel world that you will have to seek out. They are out there but fairly rare.
As far as the nut width goes, I think it depends on your playing position. If you play your guitar on your right leg and keep the neck closer to horizontal then I would recommend 48mm nut. Get yourself a good crossover and you'll likely find it has a radiused fret board and maybe a truss rod.
If you play your guitar in the classical position, with it resting on your left leg and the neck at about a 45 degree angle, then I would recommend a wider 50-52mm nut. Finding a radiused board/truss rod at this width is much more difficult however. This is where you'll find your choices limited unless you are ok with a totally flat fret board.
I found the biggest change moving over to classical was changing my playing position, from cowboy to classical. I felt alien at first and took a couple of months to feel natural. I have to admit this position allows much better fingering with the left hand, with better reach, control and accuracy. I would recommend you give this playing position a try it is worth the effort.
I found a foot stool gave me back pain, so now I elevate the neck with a Sage Guitar Support (https://sagework.org/collections/atlas-models
. That one is quite expensive but there are many other less expensive options out there on the market.
The last thing to consider is the endless spruce vs. cedar top debate. Spruce is the traditional top for classical guitars until about the 60s, when cedar became trendy. Now they are many models with that are identical except for your choice in top wood. Some prefer one or the other. I've found great guitars with either top, so I'd play as many as you can and find what speaks to you. There are a few out there with redwood tops as well.
Good luck and enjoy the journey!