Preheat oven to 400 degrees F.
Heat oil in a large skillet over medium heat. Add onion and garlic and saute 2 minutes. Add chicken and saute 5 minutes, until golden brown and cooked through. Remove half of the chicken and reserve for another use.
Stir in black beans, green chiles, and salsa and simmer 5 minutes, until sauce thickens and reduces. Remove from heat and stir in cilantro.
Arrange 4 tortillas on a flat surface. Top each tortilla with an equal amount of chicken mixture. Roll up tortillas and place side by side in a shallow baking dish. Top tortillas with shredded cheese (1/3 cup per tortilla).
Bake enchiladas 15 minutes, until cheese is golden and gooey!