if we adding a nspv protocol enable/disable flag it is also better to turn on/off announce of nspv services by the node accordingly:

void CAddress::Init()
{
    nServices = NODE_NETWORK | NODE_NSPV;
    nTime = 100000000;
}

I guess here we should make it optional also:
https://github.com/KomodoPlatform/komodo/blob/666047b4f56778927a1787a8743fbb4bbede6068/src/net.cpp#L86
Like:

uint64_t nLocalServices = NODE_NETWORK | (GetBoolArg("-nspv_msg", false) ? NODE_NSPV : 0);