What I meant was that you can try starting the process with the hardware wallet, rather than your Electrum wallet.  So, open your hardware wallet, create the transaction that you want to make, sign it, and save it.  Then import the partially signed transaction into the (non-hardware) Electrum wallet to add the second signature and broadcast.

Doing things in this order has worked for me in the past, but I use a Trezor wallet, and have never played with a multi-sig wallet using the Nano.  It sounds like you have one of each brand, so it may work with one or the other hardware wallet.