Place chicken breasts in bottom of Instant Pot.Pour chicken broth into Instant Pot and sprinkle onion powder on top of chicken.
Place lid on Instant Pot and lock in place. Make sure valve is in "Sealing" position.Set Instant Pot to High Pressure for 10 minutes. Let Natural Release for 5 minutes and then open the valve to let the pressure out.Remove the lid.
Place chicken breasts on a cutting board and shred with 2 forks.Discard the liquid in the Instant Pot.
Return chicken to Instant Pot and add Caesar dressing, Parmesan cheese, garlic powder, crushed red pepper flakes, and black pepper to taste.
Turn Instant Pot to "Saute". Cook, stirring frequently, for a few minutes to warm everything.Sprinkle parsley on top and serve.