Trim excess fat from the chicken and cut into 1 ½-inch cubes.
Select "Saute" on the Instant Pot. Allow pot to heat, it will indicate "Hot" on the display when ready.
Add vegetable oil, once hot add the garlic and onions, saute until fragrant, 1 minute.
Add in cubed chicken, saute for 2 minutes.
Add in Thai curry paste, mix to combine with the chicken and cook for 1 minute.
Add in maple syrup and 1 ½ cups coconut milk, stir to combine.
Press "Keep/Warm/Cancel" on the Instant Pot.
Make sure that the release valve is in the "Sealing" position, place the lid on the Instant Pot, turn and lock.
Press the "Manual" button on the Instant Pot on high pressure, and then set the timer to 6 minutes using the "+" or "-" buttons. It will take about 10 minutes for the pot to heat and build up pressure. You will see some steam release from the lid, and then the time will start on the display.
Once the display indicates "On" and begins the countdown at "6", then beeps when the cycle is complete.
Cover your hand with an oven mitt or towel to carefully quick-release the pressure, sliding the steam release handle to the "Venting" position, releasing all of the steam until the float valve drops down.
Remove the lid, opening the top away from you as steam will be released from the pot.
Select "Saute" on the Instant Pot, once the sauce begins to boil add in the bell pepper, zucchini, and pineapple.
Cook until the zucchini is tender, about 5 minutes.
Turn off the Instant Pot and stir in the fish sauce and ½ cup additional coconut milk.
Taste and season with more salt and pepper as desired.
Notes
Serve chicken curry with rice, cauliflower rice, or broccoli rice and lime wedges.