Storing cut up potatoes (chips/fries)
You can store your cut potatoes in the fridge. Place them in container(s) and cover them completely with plain, unsalted water. They should be fine for at least 2 or 3 days.

I don't know that it's necessary, but I usually drain and rinse them before use.

Alternatively, as you are cooking them in the oven, you could cook a large batch and then store your preferred portion sizes in the fridge or freezer, depending on how long you plan to keep them before use.