Nature experiences, especially the visual aspects of nature, have been widely used to facilitate relaxation. Fueled by digital technology, simulated visual nature experiences have gained popularity in creating healing environments that induce relaxation. However, while easily applicable, not all nature-imitating visuals lead to relaxation. How to effectively design relaxing visual nature experiences remains largely unexplored. This paper investigates how different nature qualities facilitate relaxing visual experiences and the roles of two personal characteristics (mood and nature-relatedness) play. Through an online survey and interviews, we assessed 16 nature video clips, representing eight distinctive nature qualities, and compared perceived experiences while considering the influence of personal characteristics. The results indicate four types of visual qualities (engaging, instinctive, ambient, and derivative) underlying nature-induced relaxation, and show that nature relatedness influences the degree to which nature video clips elicit relaxation. We discuss design implications for creating personalized digital nature.