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This didn't work
(Though I don't know how to do the part "create the transaction with the hardware wallet" - if you can let me know/link to a good guide on how to do that, I can give it a try)
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 a new 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. I 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.
So when I open the hardware wallet with Electrum, it doesn't show the coins I have in the non-hardware Electrum wallet
For example, let's say I have 1 BTC in the non-hardware wallet.
When I open the hardware wallet, that 1 BTC doesn't show, and I don't think I can make a txn with 1 BTC from the non-hardware wallet?
Not sure if that makes sense