As virtual reality technologies become integrated into sports broadcasting, they are reshaping how fans engage with live events. This study uses BERTopic, an unsupervised deep learning topic modeling technique, to examine how fans discuss NBA VR viewing experiences across two Reddit communities: r/nba and r/virtualreality. To identify and cluster thematic patterns in user discourse, the model employs sentence embeddings produced by the all-MiniLM-L6-v2 language model. A total of 817 comments from r/nba and 321 comments from r/virtualreality were analyzed to identify themes in user discourse. The r/nba discussions clustered four major themes: device and application ecosystem, immersive viewing experiences, court proximity and virtual ticketing, and visual comfort and cost-efficiency. In contrast, r/virtualreality emphasized hardware performance and display technologies, platform control and digital rights, content access and immersive experiences, hardware limitations and community enthusiasm. These thematic differences suggest distinct engagement models, one rooted in sensory fan experiences, and the other in technical perspectives. This study contributes to the growing body of literature on immersive media and fan engagement by offering insights into how VR basketball viewing experiences are perceived and negotiated in online communities.