If you have a working SP-farm on a VM, then make a backup of the VM before you install OOS. That way you can always roll back if you encounter any difficulties. But that said, I don't think there will be an issue because I done slightly the same thing installing a Workflow manager Farm on the same box as SharePoint without issues. Then all you need to do is to connect SharePoint with OOS and keep testing.
But I'm curious what you'll need OOS for, since it doesn't really interact with SharePoint. It "just" displays Office documents in a web browser and its a pretty straight forward process making it work in any environment. If you're not developing on OOS, then consider to install OOS on a separate machine in a real test environment like SIT or even QA.
Here are the steps for installing OOS: Deploy Office Online Server