In Belgium, the CCB's CyberFundamentals framework (CyFun) is one of the reference frameworks for demonstrating NIS2 compliance, alongside ISO/IEC 27001. It comes in four levels (Small, Basic, Important and Essential), and the level you aim for depends on your risk profile and your NIS2 category.
Many CyFun controls are evidenced by your ITSM tool: asset inventory and ownership, change control, incident detection and response, supplier management, and the review of measures by management. Configuring those processes properly gives your assessor evidence that already exists, instead of documents written for the audit.
More on the asset side: IT asset management and the HaloITSM CMDB.