This is fixed in this PR (I hope) [https://github.com/nim-lang/Nim/pull/6694](https://github.com/nim-lang/Nim/pull/6694)
As a workaround you can download the packages.json file manually and place it into ~/.nimble/packages.json
This is fixed in this PR (I hope) [https://github.com/nim-lang/Nim/pull/6694](https://github.com/nim-lang/Nim/pull/6694)
As a workaround you can download the packages.json file manually and place it into ~/.nimble/packages.json