Heat 1 tablespoon olive oil over medium high heat in a 12” oven proof skillet.* Add onions and sauté for approximately 3 minutes or until soft. Add red bell pepper, black beans and garlic and sauté for two additional minutes.
Stir in tomatoes/green chilies, spinach, all seasonings/spices and mayonnaise until well combined and spinach is warmed through. Reduce heat to low and stir in cream cheese until melted followed by ½ of cheddar until melted and ½ of Pepper Jack until melted. Stir in sour cream until well combined.
Top dip with remaining cheddar and Pepper Jack. Transfer to oven and bake for 20 minutes. Broil until cheese is golden. Serve with tortilla chips.
*If you don’t have an oven proof skillet, you can prepare in another skillet and transfer to an oven safe dish.