Add note about setting up Nitro nodes for two parties in the same network (#45)

Part of https://www.notion.so/Swap-channels-in-go-nitro-119a6b22d47280b9bcf4e339fa6ba5b4

Co-authored-by: Shreerang Kale <shreerangkale@gmail.com>
Reviewed-on: #45
Co-authored-by: shreerang <shreerang@noreply.git.vdb.to>
Co-committed-by: shreerang <shreerang@noreply.git.vdb.to>

testnet-nitro-node.md

@@ -47,7 +47,7 @@
 * Check balance of your tokens once they are transferred:
 
   ```bash
-  # Note: Account address should be without "0x"
+  # Note: Account address should be with "0x"
   export ACCOUNT_ADDRESS="<account-address>"
 
   export GETH_CHAIN_ID="1212"
@@ -131,6 +131,8 @@
 
 ## Run Nitro Nodes
 
+**NOTE**: When following this setup, Nitro nodes from two parties won't be able to communicate with each other if they are on the same network
+
 Nitro nodes can be set up on a target machine using Ansible:
 
 * In `testnet-ops/nitro-nodes-setup`, create a new `hosts.ini` file: