Gmail shortcut for open spelling corrections hides window - any way to fix?
As Chrome has an actual Minimise key command, you can change it to be something different

Before


System Prefs > Keyboard > Shortcuts > App Shortcuts
Hit + then set the app to Google Chrome, menu item to Minimise &amp; the key to something you don't use anywhere else  



That should free up  Cmd ⌘   M  just for Chrome, yet it will still function correctly elsewhere.

After



Note it adds an  Opt ⌥  version for Minimise All, which tends to be a common side effect of doing this type of replacement.