How long would a homemade pancake mix keep?
A dry mix should keep essentially indefinitely if well sealed, and these are all dry, shelf-stable ingredients. We used to mix the flour, baking powder and sugar for pancakes when camping, then add an egg and measure the milk to the top of the handle on a mug. This simpler mix kept from one year to the next in a sealed bag. Using the earliest best before date on any of the ingredients would be logical. 

The chocolate chips won't keep quite so well as my mix did - they'll possibly bloom. You could present them separately as is often done with the garnish in gift hot chocolate kits. 

If you add the liquid, then it's a few days in the fridge. So consider how you present it to achieve your goal of ease. Perhaps a big jar and n tablespoons of mix to m of milk (or whatever your recipient uses for milk), or a jar a day with a mark for how much milk to add.