Place the broth and chicken in pressure cooker. Place the frozen blocks of spinach on top. Pour on the sauce and sprinkle on the curry powder. Gently stir the curry powder into the sauce. (Do not stir the chicken into the sauce; the goal is to prevent scorching the pasta sauce on the bottom while the cooker is coming up to pressure.)
Lock the lid in place. Over high heat, bring to high pressure. Reduce the heat just enough to maintain high pressure and cook for 4 minutes for boneless chicken pieces or 12 minutes for chicken parts. Quick-release the pressure. Remove the lid, tilting it away from you to allow excess steam to escape.
Stir well. Taste the sauce, and add more curry powder and salt, if needed. Garnish portions with chopped cilantro, if you wish.