Why not? We are talking about smart contracts here and all it takes is two parties who accept the token to agree on an exchange rate, then they can "swap" their tokens with each other with that rate. I think the same principles of Atomic Swaps can be applied here too except that it all happens in one network instead of two.
I'm not sure if I understand correctly what you mean. But for atomic swaps you also need two accounts (on each blockchain, or with each token if you're using two different tokens on the same blockchain). Atomic swaps are a connection between two transactions of different tokens where none of both can be done separately, but both are technically separate.I'm not 100% sure my reasoning is correct, but the way I see it is the following:
Lightning's security is based on the principle that you always have to be able to close a channel, "freezing" the current channel state. But the "channel state" has always a maximum: the amount of the coin or token you and your counterparty (channel partner) froze when you opened the channel.
So can you simply create something new "while the channel is open" that didn't exist in your channel when it was opened? This "thing" has to "jump into your channel" in some way, but isn't the security mechanism of LN and its double-spend protection limited to the original channel partners?
Probably however you could open, in a single transaction, a lot of NFT channels with some OP_RETURN magic in a few UTXOs.
I would actually be happy if I'm wrong, because that would create lots of cool use cases
