Heat oil in a large nonstick skillet over medium heat. Add bell pepper, onion, chiles, cilantro, oregano, chili powder & cumin. Saute 5 minutes or until tender. Add tomato juice and cook until thick, about 8 minutes.
Divide vegetable mixture in half, combining black beans with one half and white beans with the other half. Mix well and set both aside.
Mix cheeses together and set aside.
Preheat oven to 325°F.
Line a 9-inch pie plate with foil, allowing 6 inches of foil to extend over opposite edges of the plate. Repeat with another sheet of foil, crossing over the plate opposite the first piece. Coat foil generously with cooking spray.
Place 1 tortilla in the bottom of baking dish.
Spread 1 cup white bean mixture over tortilla; sprinkle with 1/4 cup cheese. Top with tortilla, pressing gently.
Spread 1 cup black bean mixture over second tortilla; sprinkle with 1/4 cup cheese. Top with tortilla, pressing gently.
Repeat until all tortillas, filling and cheese is used up, ending with cheese.
Bring the edges of the foil up to center, folding to seal.
Bake for 40 minutes; let stand out of oven for 10 minutes before unwrapping. Remove foil packet from pan; unwrap. Cut into wedges and serve with sour cream.