Preheat oven to 350 degrees. Spray 12" oven-safe skillet with non-stick spray.
Cut the pepper jack cheese, cream cheese, and queso blanco into chunks and place into an oven-safe skillet (like cast iron).
Add in the garlic, spinach, and drained Rotel and diced green chiles. Sprinkle on the seasoning over the top of everything. Pour over 1 cup of evaporated milk.
Bake in the oven for about 20 minutes, or until it can be easily stirred. Stir to combine into a creamy dip.
Mix in the sour cream, parmesan cheese, and extra evaporated milk until your desired consistency is reached.
Spread out the dip to an even layer, top with 1 cup of shredded cheese. Return to the oven for another 15 minutes or until dip is gooey and bubbly.
Optionally, once it’s finished baking, turn oven to broil to toast the cheese layer on top until golden brown, about 1-2 minutes.
If needed, add a little more evaporated milk (or regular milk) to thin out the dip as it sets or when reheating it. Serve with tortilla chips for dipping.