We present results of a spectroscopic survey of bright near-infrared counterparts to X-ray point sources from a deep Chandra survey of the Galactic nuclear bulge. K-band spectroscopy has revealed 13 new Wolf-Rayet and O-supergiant counterparts to Chandra soucres. Although they are systematically softer in X-rays than the general Galactic center source population of accretion powered CVs, their X-ray colors indicate a hard component consistent with emission from thermal plasma with kT>2 keV. Such hard X-ray emission is not ubiquitous among single Wolf-Rayet and O stars but is common among Wolf-Rayet+OB binaries with colliding supersonic winds. Although we regard colliding-wind binary hypothesis as the most likely scenario, it remains possible that several of these objects are wind-accreting neutron stars or black holes in supergiant high-mass X-ray binaries, or extraordinary single stars emitting hard X-rays