Like the unmanned missions to NEOs, the specific delta v requirements will depend on the specific target. I don't know of any generic NEO mission numbers or even if calculating such numbers are possible without the target.

There are some low eccentricity NEOs whose orbits would be easily reachable from Earth. The higher the eccentricity and the closer the NEO is to the Earth's angle to the plane of the ecliptic, the easier such a target would be to reach.

The key to mission planning would be to pick one of those and design the mission around it. Done properly, much of the technology needed for such a mission would also be useful for trips to other places like Mars.