Mix salt, paprika, garlic powder, onion powder, and pepper in a bowl. Cut chicken into 3- to 4-inch pieces and place in a large resealable plastic bag. Sprinkle the salt mixture over the chicken in the bag. Seal the bag and shake to completely coat the chicken. Pour water into a multi-functional pressure cooker (such as Instant Pot(R)). Place the wire rack into the pot. Arrange chicken on the rack. Close and lock the lid. Select Meat/Poultry function; set timer for 50 minutes. Allow 10 to 15 minutes for pressure to build. Release pressure using the natural-release method according to manufacturer's instructions, about 10 minutes. Transfer chicken to a bowl. Shred using 2 forks. Add 1/2 cup of liquid from the pot and liquid smoke; mix well. Serve on buns and top with barbeque sauce.