Preheat the oven to 350F. Line a baking dish with foil.

In a bowl, combine the Dijon, olive oil, chili powder and salt. Add in the chicken breasts and stir until the chicken is coated. Place the chicken on the prepared baking dish and cook in the preheated oven until the chicken is cooked through, about 30 minutes. Set aside to cool enough to handle. Once cool, shred the chicken and set aside.

Coat the bottom of a large skillet with the olive oil. Add in the onion and cook until soft, about 5 minutes. Add the courgette and saute until it is tender, about 6 minutes. Add the garlic, beans, chili powder, cumin and salt and cook until the beans are tender, another 5 minutes. Place the mixture in a large bowl and add the cooked, shredded chicken. Set aside.

Wipe out the skillet you were using for the bean filling. Melt the butter over medium heat. Add in the garlic and jalapenos and cook until fragrant and softening, about 4 minutes. Add the flour and cook for 1 minute. Whisk in the stock, then change the heat to high, bringing the mixture to a boil. Once it is boiling, reduce the heat and simmer until it has reduced a bit and become opaque, about 5 minutes.

Transfer the sauce to a blender or food processor. Add the sour cream, the chiles, cumin, chili powder, salt and cayenne pepper. Puree until smooth.

Coat the bottom of a 9x13-inch baking dish with the green chile sauce, reserving the rest of the sauce. Fill each of the 8 tortillas with the chicken and black bean mixture, a spoonful of the cheese, and a sprinkling of cilantro. Roll up and place seam side down in the baking dish. Pour the remaining green chile sauce over the top and sprinkle with the remaining cheese.

Bake in the oven for 30 minutes, or until the sauce is bubbling on the edges and the cheese is beginning to brown. Garnish with additional cilantro leaves and serve with the lime wedges.