Place brown rice and water in the instant pot, close the lid and seal.
Cook the rice for 17 minutes on high pressure, followed by a quick pressure release.
Place the meatballs in the pressure cooker.
Add in garlic, onions and carrots.
In a small bowl, add water to the pineapple juice to make 1½ cups.
Stir in the vinegar, brown sugar, soy sauce and cornstarch.
Pour over meatball mixture.
Set cook time for 10 minutes.
Do a quick pressure release.
Remove lid, hit the sauté button, and stir in the pineapple.
Let cook until the pineapple is warm and the sauce has reached the desired thickness.