I used the customizable rocket nozzle generator by waterside to generate a convergence divergence nozzle to work with a black powder rocket engine. I printed the engine in PLA, and despite its low melting temperature, the motor held up very well and has no damage. The integrity is in tact after firing it and I would consider it re-usable. The engine had a burn time of about five seconds and an estimated 20g of thrust.

Test video in slow motion. https://youtu.be/7Pn3RLUfRmc