Banana, yogurt and kiwi are not suitable ingredients for cookie dough. Unless you add a minuscule quantity, they would make any cookie dough too wet. The moisture in cookie dough essentially comes from fat (occasionally with some egg), or you end up with something more like cake/brownies etc.

With those specific ingredients, rather switch to muffins. Find yourself a recipe (ideally for oats muffins, it will be easier to adapt as you won't have to figure out the ideal proportions of oats to flour/liquid to solid and how much baking powder is ideal for oats etc.). Substitue mashed (fairly ripe) banana + kiwi + yogurt for the liquid part (usually milk/yogurt/puréed ingredients or a mix of those in muffin recipes), and a mix of wheat flour and oats as your dry basis (usually it's half and half, or 2/3 - 1/3 for lighter muffins). Chopped walnuts don't count in this case, just add a bunch (1/3 cup or something). Don't change the rest of the ingredients such as egg/fat/salt/rising agent. Reduce the sugar content because the banana is already sweet.