Add chicken, Italian seasoning, garlic powder, salt, pepper and olive oil to a Ziploc bag. Shake to coat the chicken. Pour broth into Instant Pot and add chicken.
Scatter the spaghetti on top. Dump the sauce evenly over it. Layer the pepperoni pieces. Don’t stir. Pressure cook 4 minutes. When time is up let the pot sit for 10 minutes and then vent.