In a large mixing bowl, cream together the sugar and shortening until light and fluffy. Mix in the bananas and egg and mix well, scraping down the sides of the bowl. Mix in the vanilla.
In a separate large mixing bowl, combine the rolled oats, flour, baking soda, cinnamon, salt and nutmeg. Mix until thoroughly combined.
Add the wet ingredients to the dry ingredients and mix just until combined. It will be a wet cookie dough. Stir in the chocolate chips.
Using a 2 spoons or an ice cream scoop is a great way to portion cookies with wetter doughs like this one. Portion cookies out using overflowing tablespoonfuls on 2 ungreased cookie sheets, 12 cookies per sheet. Bake just until golden brown, 20 to 25 minutes. After 10 minutes, turn and swap the cookie sheets on each rack for even cooking. Cool on a wire rack.