Entrepreneurial intention has become perhaps the fastest growing line in entrepreneurship cognition research. Such inquiries of intention-based models generally focus on answering and predicting why an individual makes his/her decision to be an entrepreneur. However, a few limitations inspired the researcher, such as the antecedents of intentions and opportunity evaluation in front-end factors and nascent activities in back-end factors, which were excluded in past studies. In terms of entrepreneurship opportunities, this research suggests that the new paradigm could answer the following questions: Firstly, what are the main factors that influence the intentions of nascent entrepreneurs after entering the implementation stage? Secondly, why do they strive for entrepreneurial goals by means of various actions? Based on the theory of planned behavior (TPB), the research focuses on nascent entrepreneurs, examining the roles of concrete entrepreneurial opportunities and nascent activities in an existing intention-based model. How can an intention-action model with both predicting and explaining abilities be created? The sample poll was from the participants of an entrepreneurship plan financially sponsored by the Taiwan government. This work confirmed that the voluntary sample was consistent with nascent entrepreneurs and was opportunity-based. Deleting those lacking opportunities or with missing data resulted in 207 usable responses, and then, the qualitative research of 19 participants from participant observation or in-depth interviews was conducted. By way of such a multimethod analysis, the results show that the ¡§attitude toward entrepreneurial opportunity,¡¨ entrepreneurial self-efficacy, and perceived social norms are the main factors influencing entrepreneurial intentions. Besides, intentions and entrepreneurial self-efficacy dominate and influence the nascent entrepreneurs¡¦ activities to reach the entrepreneurial goals. Finally, this research identifies two research approaches: one is ¡§To Be¡¨ and the other is ¡§To Act.¡¨ The latter forms a more explaining and predictable opportunity-based ¡§entrepreneurial intention-action model.¡¨ The stakeholders of entrepreneurial policy will face the challenges of how to improve the ¡§attitude toward entrepreneurial opportunity¡¨ and how to inspire the further actions of nascent entrepreneurs.