Nondual awareness (NDA) refers to a mode of experience marked by a lack of distinction between a subject and an object. Traditions within Tibetan Buddhism customarily instruct students not to confuse NDA with other highly salient phenomena induced by deep meditation practice, what this study terms Remarkable Experiences (REs). Devotees of intensive meditation practice can confuse REs with NDA, while clinical psychologists may pathologize REs as harmful when studied outside of their traditional context or pedagogical scaffolding. Existing measures of NDA suffer from critiques relevant to their construction, validation, and methodologies, therefore novel assessments are needed. In Phase I of the psychometric section of the Nature of Mind (NOM) study, we present a battery of questionnaire items to meditators trained in nondual practices to differentiate items that reflect NDA from those that reflect REs, along with an assigned degree of confidence for each response. Items retained after item-level distribution ratings, factor analysis, and theoretical consultation with Buddhist Studies scholars will be modified to develop a questionnaire that considers the temporal evolution of phenomenological dimensions of NDA. This questionnaire will be deployed in a pilot study and three-year retreat, with subsequent adaptations for broader contemplative and clinical applications.