Add red potatoes, corn, sausage, water, shrimp boil liquid, and 2 tsp old bay to the Ninja Foodi insert and stir. Cover and cook on high pressure for 4 minutes. Once timer is complete, do a quick release and open lid once all pressure is released.
Add shrimp and mussels and 1 tsp of old bay. Stir. Cover and cook on high pressure for 1 minute. Once timer goes off, allow to natural release for 2 minutes, then quick release remaining pressure.
Combine butter and garlic powder in a separate bowl and use as a dipping sauce.
Sprinkle with parsley and serve with lemon on the side. Enjoy :)