I recently replaced my rear air shocks with Progressive 440HD shocks. I bought a set of replacement front springs at the same time. I replaced the front springs on my Shadow and they made quite a bit of improvement on the handling of the bike.
Progressive doesn't make a set of front springs specifically for the 1600 Nomad but they make a set for the 1600 Classic which is basically the same bike. They are P/N 111144. From what I read the 1600 bikes' front springs are much easier to change than the old 1500's.
The first thing I did was lift the bike slightly to take pressure off the front forks. I also put a towel over the gas tank and front fender.
Loosen the pinch bolt with an 8mm Allen head wrench or socket.
Remove the fork cap with a 22mm socket. I didn't have any problems accessing this even with the fairing on.
Remove the factory spacer. The kit includes new PVC spacers but the instructions call for using the stock spacers.
I bent a hook in an old CB antenna I had and pulled out the old spring and washer.
The new spring (below) is a tad longer and is wound differently.
Reassemble in the reverse order...Progressive spring, Progressive-supplied washer, spacer, fork cap, and pinch bolt. Repeat for the other side. It was a 20 minute job for me to do both sides. If your fork fluid is old or you want to change to a different weight you can do that, but I didn't.
The bike feels more stable on my gravel driveway and whipping around turns. The change isn't as dramatic as it was on my Shadow. It's a little harsher on speed bumps and such but not bad. It's well worth the time and cost ($60).