The angular dependence of the incremental permeability has been investigated in conjunction with the magnetic anisotropy in the Fe75.5Zr8.3N16.2 nanocrystalline thin film annealed at 450 degreesC with an external magnetic field. The nanocrystalline thin film was prepared by the rf reactive sputtering method in Ar+N-2 atmosphere. The longitudinal permeability ratio(LPR) increases with the increment of the ac drive field and decreases rapidly up to zero at near 4 Oe with the increment of the external dc field for all measurements. LPR curves show a single peak pattern since the easy axis is parallel to the direction of the measurement in contrast to the transverse incremental permeability ratio(TPR) where the double peak pattern appears due to the anisotropy effect. The large changes of LPR and TPR curves in low external fields can be useful for magnetic sensor applications.