Smarter Approaches to Nuclear Expenditures Act This bill imposes prohibitions and limitations on funding for various Department of Defense (DOD) and Department of Energy (DOE) weapons programs. Weapons subjected to prohibitions or limitations under this bill include Columbia-class submarines, intercontinental ballistic missiles, low-yield nuclear warheads, and space-based missile defense systems. The bill also requires various reports to Congress, including a joint report from DOD and DOE outlining the estimated cost savings resulting from this bill.