The BEST way for a CIO to manage the organizational impact of deploying a new enterprise-wide tool is to implement:

Deploying a new enterprise-wide tool inevitably introduces changes to people's daily workflows, roles, and skills, leading to significant organizational impact. Change management is specifically designed to address the human aspect of change, focusing on communication, training, stakeholder engagement, and support to minimize resistance and ensure successful adoption and utilization of the new tool across the organization.

Project management focuses on the technical aspects of delivering the tool on time and within budget, but it doesn't primarily address the organizational and human impact.

Risk management identifies and mitigates potential negative outcomes, but it is a component *within* a larger change or project management effort, not the overarching approach to managing organizational impact.

Resource management deals with allocating personnel and other assets, which is necessary for a deployment but doesn't directly manage the human aspect of adopting the change.