Have not personally, but you can go on youtube and watch other people do it. Seems like it can take the .32 S&W, .32 S&W Long, and .32 H&R Mag but the brass tends to not be reloadable afterwards. However, you can get a replacement cylinder that should solve that issue.
I would advise against using any ammo that is not designed for a specific gun. Slight pressure changes (especially with incorrect caliber ammo) can make a huge difference, and very often with disastrous results. The obvious question I would have is ........................why use it? What is there to gain? I have also come to the belief that almost anything on YouTube is something to put at the top of your "Don't Do" list.
First off, minor correction to rsayloriii's first post. The .32 S&W/.32 H&R rounds use the standard 7.62x38R cylinder. The only conversion cylinder available is for .32 ACP.
Now that that's out of the way, on to the question itself.
It's safe so long as you don't mind bulged/split/stuck cases that may need to be beaten out with a rod and mallet, or completely negating the Nagant's gas seal system.
IMHO, don't even bother. 7.62x38R is much more easily found (I literally tripped over a couple boxes of it at the Dunham's Sports down the road earlier today), and is usually about the same price if not a bit cheaper. Same goes for the .32 ACP conversion cylinder (which costs about half what I paid for my Nagant, if you can even find them). Cool in concept, but in practice it's kinda pointless.