Will a 72 nova suspension swap over to a 68 chevelle? Both cars have V 8 motors.

The Nova & Chevelle were 2 completely different car lines. The Chevelle used a full perimeter-type frame with controlled flex in the torque box(?) engineered in. The Nova used a unitized body with bolt-on subframes front & rear that mounted the suspension & cradled the engine. The Nova also uses leaf springs out back vs. the Chevelle's 4-wheel coils. Despite the fact that both car lines use short/long A-arm suspension with coils I really doubt very much that anything can be shared. For all the trouble, you might just as well go with those trick tubular A-arms & F-car spindles & brakes, and maybe some trick H-O Racing rear control arms (are they still in business?) and some serious wheels & tires, quick-ratio power steering & fat anti-sway bars.

Suspension - No
Front Spindles and disc brakes - YES

You would need to use your existing steering arms that bolt to the spindle that connects to the tie rod.