Pour broth and soy sauce in an Instant Pot®, then add ginger, garlic powder, onion powder, mushrooms, carrot, and bok choy. Fan lo mein noodles out on top of vegetables and gently press down to submerge in broth.
Place the lid on the Instant Pot® and click into place to close. Press the Pressure Cook button and adjust the timer to 3 Minutes.
When the timer beeps, quick-release the pressure until float valve drops. Unlock lid. Stir noodles. Serve topped with scallions and sesame seeds.