Nanocrystalline materials exhibit high-strength characteristics primarily governed by statistical nature of nonlocal cooperative grain-boundary failure processes. As the grain size reduces, the strength increases until it drops at a nano scale due to small-length-scale cooperative mechanisms of deformation and failure. Here, we review recent advances in hybrid methods of experimental and numerical analyses for measuring the strength and fracture toughness of nanocrystalline materials associated with the cooperative failure processes. An approach is a hybrid method based on in situ TEM analysis of nano-scale failure processes and measurements of nano-scale crack-opening displacements, which are then used to estimate the fracture toughness by employing an inverse finite element analysis. The nominal yield strength, the nominal plastic hardening modulus are also determined by the inverse finite element method to match numerical crack opening profiles with the experimental counterpart. Another approach is composed of AFM interferometry and nonlinear filed projection analysis. The nonlinear field projection (NFP) method is implemented through interaction integrals, for inverse extractions of nonlocal-deformation near-fields of the failure process from the measured elastic far-fields. The nonlinear field projection method together with another interior field projection method bridges the information of the atomic scale nonlocal-deformation regions to experimentally measured continuum fields of the cooperative deformation and failure processes.