CMMC Practice RM.2.141
Periodically assess the risk to organizational operations (including mission, functions, image, or reputation), organizational assets, and individuals, resulting from the operation of organizational systems and the associated processing, storage, or transmission of CUI.
Bold Coast Security Guidance
Though it's certainly possible to get value from informal risk assessments, you're going to want to aim for Level 3 compliance in this area, which is implementing a formal documented risk management program and processes.
With the available resources from NIST (NIST SP 800-30), getting this particular practice to Level 3 is attainable for just about any organization. The reason to set this target at Level 3, is that the real value in assessing and managing risk will come over time from repeatable and comparable results. Repeatable and comparable results will help guide your organization in real ways to reduce the risks you will face, and raise the consciousness and resilience of your organization by moving risk-awareness into a top-of-mind intelligence.
DRAFT NIST SP 800-171 R2
Clearly defined system boundaries are a prerequisite for effective risk assessments . Such risk assessments consider threats, vulnerabilities, likelihood, and impact to organizational operations, organizational assets, and individuals based on the operation and use of organizational systems. Risk assessments also consider risk from external parties (e.g., service providers, contractor operating systems on behalf of the organization, individuals accessing organizational systems, outsourcing entities). Risk assessments, either formal or informal, can be conducted at the organization level, the mission or business process level, or the system level, and at any phase in the system development life cycle.
NIST SP 800-30 provides guidance on conducting risk assessments.