What should I do with my business when I leave the Netherlands?

If you move to another country and you have a business in the Netherlands you need to deregister your business here (assuming all activities in the Netherlands will end).  This needs to be done at the Kamer van Koophandel  (Chamber of Commerce). You can find more information about this on https://www.kvk.nl/english/report-a-change/deregistering-a-company-or-legal-entity/

You can find a checklist of things to do when you close your business on https://business.gov.nl/ending-your-business/closing-down-your-business-or-bankruptcy/checklist-for-closing-down-your-business/