A former adviser to Senator Harry Reid is President Obamaâ??s choice to lead the Nuclear Regulatory Commission, giving opponents of a nuclear waste repository in Mr. Reidâ??s home state of Nevada another well-placed ally. The new chairman, Gregory B. Jaczko, has served on the five-member commission since January 2005. He will now serve as the commissionâ??s official spokesman and as its chief executive, overseeing day-to-day operations as well as long-range planning. [Jaczko earned his doctorate at UW-Madison]