Set Instant Pot to Saute, heat oil, and brown chicken pieces briefly; remove and set aside.
Saute onion until softened, then add garlic and ginger and cook 1 minute.
Stir in curry powder and cumin, toasting 30 seconds, then add tomatoes, broth, and coconut milk.
Return chicken (and potatoes/carrots if using) to the pot, scrape up browned bits, seal lid, and Cook on High Pressure for 7 minutes.
Quick-release pressure, stir, season with salt and pepper, and simmer on Saute for 2–3 minutes if sauce needs thickening.
Serve over rice and top with cilantro.