Add onion and garlic and cook until onions begin to soften.
Add in cubed pork and brown on all sides. (may need to do in more than one batch)
Put pork and onion mixture into slow cooker.
Add in salsa, enchilada sauce, chilies and tomatillos.
Add in cumin and salt.
Stir to combine.
Cover and cook on high for 3 hours or cook on low for four hours.
An hour before done remove 1 C of liquid from slow cooker and combine with corn starch.
Put back into slow cooker, stir and allow to thicken for remaining hour.
Meat will be tender and pull apart easily when done.
To make it in the Instant Pot:Set the Instant Pot to sauté. Add oil and then saute pork, onions and garlic for 2-3 minutes. Mix together sauce and pour over pork. Set to manual, high pressure and cook 25 minutes. Allow pressure to release naturally.