Preheat the oven to 350 degrees F (175 degrees C). Line two baking sheets with parchment paper.

Mix together peanut butter, 3/4 cup plus 2 tablespoons brown sugar, egg, baking soda, vanilla, salt, and nutmeg until combined. Mix in mini chocolate M&Ms.

Scoop out 1 1/2 tablespoon sized balls of dough and place 1 inch apart on the baking sheets. Flatten dough balls to about 1/2 inch thickness.

Bake in the preheated oven until tops of cookies begin to slightly crack, about 10 minutes. Allow cookies to cool 10 minutes on baking sheets before removing to a wire rack to cool completely.