Turn Instant Pot to saute mode and melt 2 tablespoons of butter. Add onion, carrots, and celery. Saute until softened, about 7 minutes. Add garlic and saute for another minute. Then add flour and saute for 1 more minute. Turn Instant Pot off.
Add chicken broth, pepper, salt, and dill weed. Stir, then add chicken. Cook on high pressure for 10 minutes. Let natural release for 10 minutes. Remove chicken and shred with two forks, then return to pot.
In a small bowl, stir together flour, baking powder, salt, pepper, and garlic powder. Cut in butter with a pasty cutter or two knives. Stir in buttermilk and continue stirring until a soft dough forms. Drop dough in teaspoon sized drops evenly over top of soup.
Turn Instant Pot to high pressure and cook for 5 minutes. Let natural release for 5 minutes, then use a wooden spoon to open valve to finish releasing (the spoon is so that you don't burn yourself on the hot steam escaping). Serve with chopped fresh parsley.