TIA,
Stu
And for completeness: download and build from source works well for M1 macOS, following the hints in https://github.com/nim-lang/Nim/issues/16211.
git clone https://github.com/nim-lang/Nim
cd Nim
git clone -q --depth 1 https://github.com/nim-lang/csources_v1.git csources
./build_all.sh
git clone -q --depth 1 https://github.com/nim-lang/csources_v1.git csources
this step is un-necessary (and not even used, since we now use csources_v1). instead, follow docs (https://github.com/nim-lang/Nim):
git clone https://github.com/nim-lang/Nim
cd Nim
sh build_all.sh