The thing is that all 3 nodes run on different ports, both -rpcport and -port, and I will give you an example of -daemon command that I execute for each of these nodes:
multichaind nchain1 -datadir=/home/nprnic/node2 -rpcport=8360 -port=8361 -daemon
multichaind nchain1 -datadir=/home/nprnic/node2 -rpcport=8362 -port=8363 -daemon
multichaind nchain1 -datadir=/home/nprnic/node2 -rpcport=8364 -port=8365 -daemon
So, as you can see, every single -rpcport and -port is different.
I can start node1, but not the other two...