Competing electric dipole orders arising from nearly degenerate free-energy landscapes underpin a broad range of emergent functionalities in complex oxides, yet remain largely unexplored in two-dimensional van der Waals materials. Here, we report direct evidence for the coexistence of polar and antipolar states in niobium oxide dichloride (NbOCl2) under ambient conditions. Through concerted microscopic structural characterization and mesoscopic domain imaging in conjunction with first-principles calculations, we establish that the two dipole-ordered phases are nearly degenerate in energy and form intricately intertwined domain structures across multiple length scales. We further demonstrate a reversible, strain-driven transition from the antiferroelectric to the ferroelectric state under continuous in situ uniaxial tensile strain, revealing an exceptionally flat energy landscape and strong susceptibility to mechanical stimuli. The strain response further suggests an intimate coupling between electric dipole order and the Peierls distortion of the quasi-one-dimensional Nb-Nb chains, linking ionic polarization to the underlying electronic structure. Together with the isolated flat band in NbOCl2, these findings establish a promising platform for exploring strain programmable ferroic functionalities and ferroelectric control of correlated electronic states in van der Waals materials.