Nematic liquid crystals possess only orientational order. In liquid crystal cells, their texture is mainly controlled by anchoring conditions and by the values of the Frank elastic constants. Given homogeneous boundary conditions, nematic liquid crystal cells tend to show homogeneous equilibrium textures, even if complex transient states are sometimes observed (under a sudden change in voltage, for example). Any large changes in the elastic constants, however, can significantly impact the cell arrangement and give rise to inhomogeneous textures. In this work, we studied the evolution of the textures of chiral nematic mixtures whose bend elastic constant, K₃₃, becomes very low near the transition to the twist-bend nematic phase. This low value results in the formation of voltage-induced periodic striped textures which are associated with a heliconical instability. We also demonstrated that their wavelength can be tuned by adjusting the voltage.