Mix together milk, pumpkin, egg, oil, and vinegar. Combine flour, brown sugar, baking powder, baking soda, and spices in a separate bowl. Add pumpkin mixture to dry ingredients and stir till just combined.
Heat skillet over medium low heat and grease with butter or cooking spray. Pour 1/4-1/3 cup batter into the skillet. Scatter some chocolate chips on top. Cook until browned and bubbles form on top (1.5-2 min). Flip and cook until other side browns and center is set. Repeat with remaining batter.