In a small bowl add the melted butter, chicken broth, lemon juice, cornstarch, garlic, dill, salt and pepper. Stir until combined. Set aside.
Add the potatoes to the bottom of the pressure cooker. Add the chicken breasts over the potatoes.
Pour over the lemon dill sauce over the potatoes and chicken.
Secure the lid. Press the poultry function, set the pressure to HIGH and set the time for 15 minutes. Be sure the steam release valve is in the "Seal" (closed) position. Press start.
When the cooking time is complete, and the pressure has been released serve the chicken and potatoes with the sauce drizzled over.