Combine the first 5 ingredients, for the dry rub, in a small bowl and stir to combine. Set aside.
Carefully remove membrane from back of baby back ribs with a sharp knife, if necessary. Cut the ribs into 3 or 4 equal-sized parts and work the dry rub into each section on both sides. Set aside.
Add beef broth or water to Instant Pot and insert the metal rack. Place the seasoned ribs on their sides on top of the insert. (Do not stack them flat on top of each other).
Lock the Instant Pot lid into place and turn the pressure valve to “Sealing.” Set the manual setting to high for 30 minutes.
Meanwhile, line a large, rimmed baking sheet with parchment paper or a silicon mat and set aside and preheat the broiler to high.
Once cooking time is complete, do a quick release by turning the sealing valve to the “Venting” position. Unlock and remove the Instant Pot lid.
Transfer ribs to prepared baking sheet. Brush ribs with a generous amount of BBQ sauce on each side.
Broil the ribs for 3-5 minutes or until bubbly and beginning to char. Remove from oven and cool slightly. Serve immediately with extra BBQ sauce for dipping.