This research aims to explore the role of AI-powered chatbots in providing mental health support. This research conducted a systematic literature review (SLR) on AI-powered chatbots in delivering mental health support from 2020 to 2024. The research includes 24 papers selected from a total of 392 retrieved publications from two high-quality, reputable journals. The selected papers were filtered based on four inclusion and exclusion criteria with at least one citation per paper. The analysis identified four roles of AI-powered chatbots in delivering mental health support: 1) guiding users through cognitive behavioral therapy (CBT) techniques, 2) diagnosis and assessment, 3) monitoring and feedback, and 4) providing a real-time emotion recognition platform. Additionally, four factors motivating AI users to seek mental health support were identified: accessibility, cost-effectiveness, immediate assistance, and comfortability. Finally, four factors contributing to the application of AI-powered chatbots in delivering mental health support are 1) Natural Language Processing (NLP), 2) user-friendly interfaces, 3) data privacy and security, and 4) emotional intelligence.