Which items on this list can be purchased on chol hamoed (after peasach has already started)?
On Pesach even a miniscule amount of Chametz is a problem and isn’t nullified in 60 (Batel B’shishim). Anything that was Batel before is still ok.
So anything packaged would be fine. It was produced before Pesach. Anything open such as Starbucks where even a small crumb can get in ON Pesach - we avoid.
Here’s an old post of interest.