Anybody know if I can use stock parts and put power disc brakes on a 63 Nova? It has been changed to 5 lug drums already. Thank y'all.

Yes you can. We did this to my brothers 67 Nova.
We used parts from a Chevelle. Get all the brackets from the Chevelle setup. Unbolt all of your existing brake hardware, right down to the spindle. Bolt the caliper bracket on with one bolt to the steering arm loosely. Pivot it up to intersect your existing spindle. You will see how it interferes with the existing bolt boss. Scribe a line on the boss and cut it off. We used a sawzall. Leave a bit of extra material. File it flatter. Now install the bracket. Everything else is a bolt together. Cant remember what application for the rubber hose. But on early Chevelles , I use a 68-69 Camaro from hose.
For the Power brakes, just buy the right one from your local parts store and pay the core.