I have to snicker at the guys who demand "proof" or "data" as if those who offer personal
experience have some ulterior and/or deceptive motive...
Here is what I have witnessed over 28+ years of metallic handgun loading. You will get no data and zero evidence. Disregard all of this post if it suits you.
If the brass is the same headstamp and from the same era, the nickel plated brass will not last as long as the non-nickel brass. You'll either get mouth splits with low pressure stuff or you'll get lengthwise splits in the body of the case in high-pressure rounds.
Which of each? Plenty of mouth splits in 17k psi .38 Special brass, and in my nickel, my most prevalent has been R-P nickel. Excellent brass and not even suggesting that nickel R-P won't last long... merely saying that non-nickel will last LONGER.
High pressure? ATK .327 Federal Magnum, 45k PSI. Federal and Speer, all came from the same place. Lengthwise splits in the body of the case in both nickel and brass, more prevalent in nickel.
The good part of nickel brass? Oh sure, lots of good and I like it. It does not get as dirty as brass does, and cleans up far easier. Can be easier to spot when scattered across your favorite range.
Absolutely leans toward assisting all chambering and ejection, whether you are talking semi-auto or revolver, this brass is simply more slippery and the difference is easily detectable when working with any revolver where you do the work, it's not obvious in a pistol where the pistol does that work, but rest assured that the pistol is feeling less resistance in both directions.
If it's a common chambering (.38, .357) I'd probably choose nickel over brass but for sure, I'm not that picky and both are welcome.
If it's a scarce chambering (.32 Long, .327 Federal) and I need the longevity because I don't find the stuff anywhere and I even lose some of what I have... yes, make mine non-nickel because like most handloaders, I am frugal and I want my supply to last.
Feel free to completely disregard the experiences I have had & relayed here, but you'll be wasting breath to convince me that I haven't witnessed these things. Many, many, many times over many years.