Line a muffin tin with paper liners or spray with cooking spray.
Combine baking mix, Greek yogurt, eggs, oil and water in a bowl. Stir until mixture forms a batter. Fold in chocolate chips.
Spoon batter into prepared muffin tin, filling each cup ⅔ of the way full.
In a bowl mix oats, brown sugar and butter until well combined.
Sprinkle oat mixture on the top of batter. Bake in preheated oven for 15 - 20 minutes or until wooden toothpick inserted comes out clean. Remove from oven, cool completely, then serve.