In a large nonstick skillet over medium-high heat, place the olive oil and onion
and saute until the onion is translucent. Add the ground beef and brown; drain
the fat.
Stir in the tomato sauce, black beans, water, green chiles and taco seasoning
mix. Bring to a boil, reduce the heat, cover and simmer 5 minutes.
Prepare the corn muffin mix according to package directions. Drop small
spoonfuls of batter over the meat mixture in the skillet; don't worry if there
are some small uncovered places. Cover and cook over medium heat 15-17 minutes
until the batter is cooked through.
Sprinkle the mixture with the cheese and green onion. Re-cover and cook 3-4
minutes over low heat until the cheese melts.