Gov. Brian Sandoval signed legislation Thursday legalizing online gambling in Nevada, capping a dizzying day at the Legislature as lawmakers passed the bill through the Assembly and Senate as an emergency measure.Nevada wanted to beat New Jersey, its East Coast casino rival, to the online-gambling punch. New Jersey Gov. Chris Christie previously vetoed an online-wagering bill but has indicated he might sign an amended version next week.Sandoval and Nevada legislative leaders said it was important for Nevada to remain at the forefront of gambling regulation.“This is an historic day for the great state of Nevada,” Sandoval said, flanked by dozens …