Resistive and capacitive switching in capacitor metal/nanocomposite/metal (M/NC/M) structures based on (Co-Fe-B)x(LiNbO3)100-x NC fabricated by ion-beam sputtering with metal content x ≈ 8-20 at. % is studied. The peculiarity of the structure synthesis was the use of increased oxygen content (approximately equal to 2 × 10-5 Torr) at the initial stage of the NC growth. The NC films, along with metal nanogranules of 3-6 nm in size, contained a large number of dispersed Co (Fe) atoms (up to approximately 1022 cm-3). Measurements are performed both in dc and ac (frequency range 5-13 MHz) regimes. When switching structures from high-resistance (Roff) to low-resistance (Ron) state, the effect of a strong increase in their capacity is found, which reaches 8 times at x ≈ 15 at. % and the resistance ratio Roff:Ron ≈ 40. The effect is explained by the synergetic combination of the multifilamentary character of resistive switching (RS) and structural features of the samples associated, in particular, with the formation of a high-resistance and strongly polarizable LiNbO3 layer near the bottom electrode of the structures. The proposed model is confirmed by investigations of RS of two-layer nanoscale M/NC/LiNbO3/M structures as well as by studies of the magnetization of M/NC/M structures in the pristine state and after RS.