Instant Pot® Chicken Tinga Tostadas

Step 1
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler to low.

Step 2
Stem and seed chile peppers. Place peppers in a bowl and cover with boiling water. Soak for 10 minutes. Drain, reserving 1/2 cup soaking water.

Step 3
Rub tomatoes with 1 teaspoon oil and place in a baking dish.

Step 4
Broil tomatoes in the preheated oven until they are starting to split and sizzle, 5 to 7 minutes. Remove from the oven.

Step 5
Place chile peppers, reserved soaking water, tomatoes, roasted red pepper, 1/2 of the onion, whole garlic cloves, oregano, and cumin in a blender. Blend on medium or high speed until very smooth.

Step 6
Turn on a multi-functional pressure cooker (such as Instant Pot®), add remaining 3 teaspoons oil, and select Saute function. Add remaining onion and saute until tender and starting to turn brown, 2 to 3 minutes. Add minced garlic and saute for 1 minute. Pour in blended sauce. Add chicken, ensuring it is covered by the sauce. Cancel Saute function.

Step 7
Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 18 minutes. Allow 10 to 15 minutes for pressure to build.

Step 8
Release pressure carefully using the quick-release method according to manufacturer's instructions, about 5 minutes. Unlock and remove the lid.

Step 9
Select Saute function. Shred chicken and cook until sauce is thick and combined with meat, about 10 minutes. Season with salt and pepper.

Step 10
Serve on tostada shells.