In this paper, and as a tribute to our friend and collaborator Barbara White, we explore how Generative AI (GenAI) technology can create stimulating new learning environments that support complex sense-making activities. We present a case study of expert use of a chat-based generative AI tool to examine the feasibility of using human-computer collaborative interactions to support metacognition and sociometacognition, i.e., knowledge about, awareness of, and ability to regulate individual (meta) and collective (sociometa) cognition. Our questions are: (RQ1) Is it possible for human-GenAI collaborative interactions to support metacognition, and (RQ2) Is it possible for them to support sociometacognition, i.e., knowledge about, awareness of, and ability to regulate individual (meta) and collective (sociometa) cognition. Our initial findings, though limited by the exploratory, case-based methods used, indicate the promise of GenAI as a valuable social interaction and cultural simulation tool for learners to practice collective sensemaking skills. Although the limitations of chat-based GenAI technologies, including their tendency to provide definitive answers unsupported by evidence, are worth mentioning, our findings contribute to the ongoing conversations around how to develop technologies to support learners' argumentation practices. Accordingly, this study has important implications for future research and practice on using chat-based GenAI as a partner for students to practice the knowledge and skills connected to argumentation and scientific claims, especially in larger courses or broader audiences.