Take the arborio rice in the inner steel pot. If you want you can rinse the rice once or twice in a small colander or strainer (which is what I do). You can also use basmati and jasmine rice. If using basmati or jasmine rice reduce the milk quantity to 2.5 cups.
Add unrefined cane sugar, a pinch of salt and whole milk. You can use white sugar instead.
Stir and mix with a spoon.
Cover and secure the instant pot with its lid and position the steam release handle to sealing.
Press the porridge setting button which has an auto timing of 20 minutes.
After 20 minutes when you hear the beep sound, give a natural pressure release (npr) of 10 minutes.
After 10 minutes lift the steam release handle and when the float valve falls down, open the lid.
The rice would have formed a few lumps in some places. So break these lumps with a spoon. No need to break all the lumps. Just mash a few.
Add vanilla extract, ground cinnamon and ground nutmeg.
Add your choice of nuts. I added some and golden raisins.
Press the sauté button and set time to 4 to 5 minutes on normal mode. Once the beep sound is heard and you see the pudding simmering, stir often so that the pudding does not burn or scorch from the bottom.
Break any lumps if any while stirring. You can cancel the sauté mode before the set time of 4 to 5 minutes. Keep in mind the consistency you want as on cooling the pudding thickens more. Stir and simmer till the rice pudding reaches the desired consistency.
Serve pudding hot or warm or chilled. When serving garnish with some sliced almonds and raisins.