I think there was a time a dude did this for real on a Cessna and crashed it as the part almost immediatly failed.

Unless you have a metal 3D print, or can print in exotic ultra strength materials, you just can’t do this.

I think even if you have a metal 3d printer, it would still not be suitable for anything where strength of the piece is critical. Iirc, metal 3d printing basically just joins metal filings together using some kind of medium, making is no much weaker than a forged or machined piece.
They use a laser to melt the top layer of a bed of metal powder, lower the bed, spread more powder, repeat. It results in a generally more porus part than cast or forged material, thus weaker, but can make otherwise impossible to manufacture geometries that can be lighter weight, which can reduce the strength requirements as well. A jesus nut is not an application you skimp on strength lol