Whisk together the mayonnaise, sour cream, and packet of taco seasoning mix in a large bowl until smooth.
To the bowl, add the southwest corn, mild green chiles, green onions, jalapeno pepper, and mexican cheese blend. Stir together until all the ingredients are fully combined.
Cover the bowl with plastic wrap and refrigerate for a minimum of 2 hours, up to overnight, or until the Mexican street corn dip is completely chilled.
Before serving, transfer the chilled dip to a serving bowl and garnish with a sprinkle of chopped cilantro or sliced green onions, cotija cheese and a pinch of chili powder if desired.
Notes
Be sure to drain the southwest style corn very well before adding to the rest of the ingredients to ensure the creamy texture of the dip does not get watered down too much as it sits and chills.
Full-fat sour cream and mayonnaise are best to use to ensure your dip is nice and creamy.
For added heat, you can add additional minced jalapeno or a pinch of cayenne pepper to the corn dip mixture if desired.