In the pot of a slow cooker, add green chiles, shredded cheese, cream cheese and salsa. Cook on low heat for 20 minutes until cheese has started melting. Stir together well.
Stir in heavy cream and cook 30 minutes. Stir really well.
Add in frozen spinach and cook another 30 minutes.
Please note--you may need to add extra cream if mixture gets too thick.
******Using blocks of cheese and shredding yourself works better in this recipe, however I have used pre-shredded cheese with no issues. Just know that using pre-shredded cheese takes longer to melt and requires more stirring.