I highly recommend adding a workflow_dispatch trigger so that you can test nightly builds when needed, and from a branch, instead of having to wait for the next nightly run on master.

cardano-ledger does this here and here.

Also, you might want to change the time of the nightly run slightly. A lot of things get scheduled on the hour on GitHub, so the load is likely to be less if you schedule at a random minute past the hour.