Honestly, I'm not sure. My needs were very minimal, one Deno stdlib import, and one third party module import (for ini file parsing).
https://deno.land/x/ has their third party module ecosystem, but it's all just JS in the end, so I think think there's anything making it so you
couldn't use the NPM ecosystem.
I found this article[1] which seems to indicate if the node packages use ES modules you can use import them as is, or if not it says JSPM can help with that.
1: https://medium.com/samsung-internet-dev/using-node-modules-i...