There are two ways to get a projectile to curve. One, fire is ballistically, meaning gravity is on and flight controls/propulsion are off. Second, reverse it, but give the missile instructions. This is what the nuke does. It flies up, turns 90 degrees towards the target, then another 90 degrees when it's very close to the target. A rectangular trajectory.
Parabolic or parabolic-ish trajectory could be easily programmed similar to how it's done in MMLs: Set the missile's turn radius to be a function of it's distance from the target upon launch. With calibration, this will make an eliptical trajectory. It will also clear terrain easily, except possibly tall mountains on short distance shots. The main problem with this would be that it would make nukes spend a lot more time in the air generally, and this problem would be much worse for further targets.
