The main result of this paper is an almost-everywhere hierarchy theorem for nondeterministic space that is as tight as the well-known infinitely-often hierarchy theorems for deterministic and nondeterministic space. In addition, we show that the complexity-theoretic notion of almost-everywhere complex functions is identical to the recursion-theoretic notion of bi-immune sets in the nondeterministic space domain. Finally, we investigate bi-immunity in nondeterministic and alternating time complexity classes and derive a similar hierarchy result for alternating time.