Actually, asteroid Bennu has a small chance of hitting us in 159 years. Thing is, Bennu is 1600 feet across, made of loose rubble, and is affected by heat from the sun pushing it in a way that is impossible to calculate precisely, so, in 159 years, we might be way off. Bennu passes us every 6 years. The 1/2 pound soil sample landed in western Utah and is being analyzed to better understand the asteroid in the hopes of dealing with it.
Based on that description a small nuke is all that is needed. That will fracture it into smaller bits, easily dealt with by our atmosphere.