Is there a way to detect if a part is touching another part while it's CFramed inside of it?

If you're trying to detect a collision it won't work. The parts are perfectly inside each other so they'll never be able to move, nullifying any collision-based code. The only solution I see is to use Magnitude, basically saying that if they're a certain distance from each other then it can be detected. Other than that I don't see any other way of finding out when they touch. Even then, it kind of assumes that their centers are very close to each other, which they may not be.