Can't install nigtly toolchain

[selassje]

rustup --version
rustup 1.22.1 (b01adbb 2020-07-08)

rustup toolchain install nightly
info: syncing channel updates for 'nightly-x86_64-pc-windows-msvc'
info: latest update on 2020-09-12, rust version 1.48.0-nightly (99111606f 2020-09-11)

nightly-x86_64-pc-windows-msvc unchanged - (toolchain not installed)

info: checking for self-updates

[ehuss]

This should be fixed in the next nightly via rust-lang/rust#76639.