School nurses encounter many students presenting with mental health needs. However, school nurses report that they need additional training and resources to be able to support student mental health. This study involved a multilevel, stakeholder-driven process to refine the Mental Health Training Intervention for Health Providers in Schools (MH-TIPS), an in-service training and implementation support system for school health providers, including school nurses, to increase their competence in addressing student mental health concerns. Findings highlighted the importance of mental health content including assessment, common factors of positive therapeutic mental health interactions, common elements of evidence-based mental health practice, and resource and referral mapping. Additionally, multifaceted ongoing professional development processes were indicated. Study findings indicate that, with recommended modifications, the MH-TIPS holds promise as a feasible, useful intervention to support school nurse practice and ultimately impact student mental health and educational outcomes.