You can configure a microflow button to ignore page validation errors and still run, but I don’t see this option for nanoflow buttons. Is there any way around this or do I just need to replace nanoflows with microflows when I want to ignore validation errors?
Don't put validations at page level. That’s a best practise in general, as these are client side and actual no validations at all, just user interaction.
Always put your validations in microflows, before committing the object(s) in an microflow.