When you install Opera, in the installer, you can click "options". There you will see an option to import data from your default browser. It's actually checked by default. If you choose/keep that option with Chrome as the default browser, Opera will import Chrome's passwords etc. and not just bookmarks.
If Opera is already installed, you should be able to goto the URL opera://settings/importData in Opera, make sure passwords are checked and import from Chrome.
Another way to do just passwords is to export them from Chrome via chrome://settings/passwords, turn on opera://flags/#PasswordImport in Opera and import the password file by going to opera://settings/passwords, clicking the kebab menu on the side (3 dots) and choosing "import".