To understand the origin of nuclear (\(\lesssim\) 100 pc) millimeter-wave (mm-wave) continuum emission in active galactic nuclei (AGNs), we systematically analyzed sub-arcsec resolution Band-6 (211-275 GHz) ALMA data of 98 nearby AGNs (\(z <\) 0.05) from the 70-month Swift/BAT catalog. The sample, almost unbiased for obscured systems, provides the largest number of AGNs to date with high mm-wave spatial resolution sampling (\(\sim\) 1-200 pc), and spans broad ranges of 14-150 keV luminosity {\(40 < \logL_{\rm 14-150}/({\rm erg\,s^{-1}}) < 45\)}, black hole mass \(5 < \log(M_{\rm BH}/M_\odot) < 10\), and Eddington ratio (\(-4 < \log \lambda_{\rm Edd} < 2\)). We find a significant correlation between 1.3 mm (230 GHz) and 14-150 keV luminosities. Its scatter is \(\approx\) 0.36 dex, and the mm-wave emission may serve as a good proxy of the AGN luminosity, free of dust extinction up to \(N_{\rm H} \sim 10^{26}\) cm\(^{-2}\). While the mm-wave emission could be self-absorbed synchrotron radiation around the X-ray corona according to past works, we also discuss different possible origins of the mm-wave emission; AGN-related dust emission, outflow-driven shocks, and a small-scale (\(<\) 200 pc) jet. The dust emission is unlikely to be dominant, as the mm-wave slope is generally flatter than expected. Also, due to no increase in the mm-wave luminosity with the Eddington ratio, a radiation-driven outflow model is possibly not the common mechanism. Furthermore, we find independence of the mm-wave luminosity on indicators of the inclination angle from the polar axis of the nuclear structure, which is inconsistent with a jet model whose luminosity depends only on the angle.