Nested Petri nets (NP-nets) is an extension of the Petri nets formalism within the "nets-within-nets" approach, when tokens in a marking are themselves Petri nets which have autonomous behavior and synchronize with the system net. The formalism of NP-nets allows modeling multi-level multi-agent systems with a dynamic structure in a natural way. In this paper we define branching processes and unfoldings for conservative NP-nets, i.e., NP-nets with a persistent set of agents. We show that NPnets unfoldings satisfy the fundamental property of unfoldings, and thus can be used for verification of conservative NP-nets in line with classical unfolding methods.