Jeryray,
Did you pull the clip pin out of the seating die and look at the two ends of the Dillon seating ram? The are reversible. One end is for round nose and the other is for semi-wadcutters. Pick the one that fits your bullets best by taking that stem out and trying both ends on one of your bullets. You can also radius and polish the edges with some emery cloth and crocus cloth, respectively, while you have it out.
If you do end up using the opposite end of the stem from the one you are using now, you will want to readjust the die. The easiest way is to back out the adjustment several turns, put one of your already-finished rounds at the seating station, run the press ram up, then tighten the die adjustment back down again until it makes solid feeling contact with the bullet.
On nickel-plated brass, use some care. The nickel is harder than brass and while it simply wears off some brass gradually, it flakes off others. The flakes can embed in your sizing die carbide ring and scratch other cases run through the die. If you put a light coat of spray case lube on the brass before resizing, it will help prevent this problem. It's just added bother.
I once bought 500 nickel-plated .308 cases with the idea the plating would help me segregate my brass from other shooter's brass at matches. The problem was the nickel reflects the color of grass and dirt accurately, so it proved harder to find. The matches only allowed us a limited amount of time to police brass between relays, and in the end, that nickel-plated camouflage caused me to lose more cases than when other shooters were picking my brass up accidentally.
The main advantage nickel has is how much longer you can keep it in leather belt loops and pouches before it starts to corrode. Police liked it in the revolver days for this reason. I wouldn't be surprised if some parts of the country still had that. Nickel probably resists weather conditions better in general. But they have to pickle (surface etch) brass to plate it and the brass is usually weakened some by that. Combined with the lower flexibility of nickel, you may find these cases develop mouth splits earlier than all-brass cases do. There seem to be differences in nickel plating process such that some cases suffer this and some don't. There's no sure prediction one way or the other.
The bottom line, though, is I found nickel to be more trouble than it's worth. YMMV, but just some things to think about for future purchases.