Ok, but please note Nesticle it's an old, buggy and discontinued emulator (since 1998). I can't recommend it these days. FCEultra, VirtuaNES, NEStopia, NNNesterJe or Nesten are updated and very good emulators.
Btw, looks that FCEultra Netplay it's buggy also and undocummented afaik. Looks like a Peer to Peer network play, but I won't expect too much about it, I'm sorry.