I m confronted to someone who states that Satoshi Nakamoto never compared Bitcoin to gold in the monnetary sense (not about mining).
However, I m sure to recall a quote from Satoshi stating Bitcoin is digital gold which was used several years ago in the debate of Bitcoin vs Bitcoin cash as an argument that Bitcoin is a store of value and not a meant of payment.
I m failing to find it again. The only thing I found is about Bitcoin mining, but this isn t in the meaning I need to prove.
Since you're saying it was in a debate a few months ago and you've mentioned Bitcoin cash, you probably mean Craig Wright, not Satoshi Nakamoto. While some believe that Craig is Satoshi (and he claims this himself), he's widely considered to be a fraud, so please take that into account. But anyway,
here's a link to Faketoshi saying something about Bitcoin being digital gold. Maybe he said it on other occasions as well, but there are some of his arguments here as well. As for Satoshi (for texts that we have strong reasons to believe were written by Satoshi), I don't think this person ever said anything like that, but I am not sure. You can try to go through Satoshi's forum posts to see if you can find anything.