In a small bowl, mix together sour cream and taco seasoning.
In a 9 x 9 inch baking dish or 9 inch pie pan, spread mashed black beans evenly in the bottom.
Spread guacamole evenly over the black beans, then spread the sour cream mixture over the top of the guacamole.
Sprinkle Pico de gallo over the sour cream mixture, then top with crumbled Cotija cheese and shredded cheddar cheese.
Garnish with chopped cilantro (optional).
*Cotija cheese can be found in most grocery stores by specialty cheeses (it's a Mexican cheese), or next to the regular cheese. It's usually found in rounds, like brie cheese. If you can't find it, you could also substitute feta cheese.