Combine ground beef, breadcrumbs, egg, onion, salt, garlic powder, and black pepper in a medium bowl.
Mix together until fully combined. Take heaping tablespoons and roll meat mixture into golfball-sized balls.
Press saute button on Instant Pot. Pour in olive oil.
Once olive oil is heated up, add in meatballs in a single layer. Work in batches, if needed.
Let meatballs brown, without moving, aproximately 1 minute. Turn meatballs over and let them brown on the other side for another minute.
Remove meatballs and set aside.
Pour in water and deglaze bottom of pot.
Add meatballs back into instant pot. Pour Stubb's Bar-B-Q Sauce over meatballs.
Close lid and set pressure release to sealing.
Press manual or pressure cook button and set to 4 minutes.
Natural Pressure Release.
Remove lid and serve instant pot meatballs on toothpicks, with sauce drizzled over them.