We investigated the experiences of 15 parents and their tween children (ages 8-12, n=23) during nature explorations using the NatureCollections app, a mobile application that connects children with nature. Drawing on parent interviews and in-app audio recordings from a 2-week deployment study, we found that tweens experiences with the NatureCollections app were influenced by tensions surrounding how parents and tweens negotiate technology use more broadly. Despite these tensions, the app succeeded in engaging tweens in outdoor nature explorations, and parents valued the shared family experiences around nature. Parents desired the app to support family bonding and inform them about how their tween used the app. This work shows how applications intended to support enriching youth experiences are experienced in the context of screen time tensions between parents and tween during a transitional period of child development. We offer recommendations for designing digital experiences to support family needs and reduce screen time tensions.