The present work investigates how the substitution of Ni for Fe in the amorphous precursor of the high flux density Fe–Si–B–P–Cu (Nanomet®) alloy avoids the creation of detrimental pre-existing nuclei in the amorphous precursor as a step forward for improved amorphization capability, retains homogenous nanocrystalline structure with excellent soft magnetic properties, and affects the mechanical properties in terms of reduced hardness and Young's modulus. This has been achieved by adding Ni of various concentrations (0–8 atomic %). The investigation includes structural characterization, calorimetry, optimization of annealing temperature, extensive magnetic characterization and nanoindentation to assess the mechanical properties. The excellent soft magnetic properties demonstrate a strategy to deploy the nanocrystalline ribbons where freedom of device design is a limiting factor for electrodynamic energy conversion applications.