This has been "beat to death" on this, and other forums, for years. There are those who believe that the nickle is harder than the die and will damage the die if, the nickle chips or flakes. There are those who have been using nickle brass for years without any problems.
I'm one of the latter group. My theory is, if the nickle is harder than the die, then it is REALLY harder than the barrel and, would scratch the chamber worse than the die. Regardless of what kind of brass you use, just remember to keep it, and the dies, as clean as possible and you should have minimal problems.