Rust nightly can't see WASM toolchain

[hally9k]

There's an issue with the latest rust nightly, this appears to affect substrate as well. This results in the following error when trying to build the node-template: Rust WASM toolchain not installed, please install it!

Sort term solution provided by @holygits to use an older rust build:

rustup toolchain uninstall nightly
rustup toolchain install nightly-2020-08-23
rustup target add wasm32-unknown-unknown --toolchain nightly-2020-08-23