Place steamer basket into the instant pot. Add in 1 cup water. Pour in frozen meatballs.

Add chopped peppers, onions, and mushrooms to the top. Place lid on the pot. Set valve to sealed position. Press pressure cook or manual button and set time to 6 minutes. 

Once the instant pot stops counting quick release the pressure via the valve. Remove all the meatballs and vegetables to a bowl. Remove steamer basket. Remove insert and drain liquid. Replace insert back into the instant pot.

Place 1 and 1/2 cup water into the instant pot. Pour in gravy packs and whisk well. Set instant pot to saute mode. Then add all the meatballs and vegetables back into the pot. Stir often until gray thickens up around the meatballs. Turn off saute mode.

Serve on hoagie rolls with provolone or parmesan cheese.