Add 2 cups of water in Instant Pot inner pot. Put the trivet in there.
Rinse rice in water, drain.
Place the rice in heat-proof glass or stainless steel bowl. Add 1½ cups water to cover the rice. Place this on top of the trivet.
Close the lid, set steam release handle to sealed. Cook at high pressure for 15 minutes, then allow to release pressure naturally.
While rice is cooking, peel and slice mango. Cut mango into bite size pieces.
Remove rice bowl from instant pot and add coconut milk, sugar, and salt. Mix well.
Serve in individual bowls with rice and mango side-by-side.