In a medium bowl, combine the softened cream cheese, mayonnaise, and sour cream. Mix well until smooth and creamy.

Stir in the shredded cheddar cheese, grated Parmesan cheese, diced green chilies, garlic powder, onion powder, and black pepper. Mix until fully combined.

Taste and adjust seasoning, adding more salt or pepper if needed.

Refrigerate the dip for at least 1 hour to allow the flavors to meld.

Before serving, garnish with chopped green onions if desired.

Serve with crackers, chips, or fresh veggies for dipping.