Although USPS clerks may answer differently, the key to the discussion is the thickness of the bubble envelope. If it is over 1/4" with contents is CANNOT go at a letter rate. It is, by definition, a package. There are different rate tables for letters and packages and you are not allowed to use the cheaper letter rate to send a chip in a bubble envelope.

That said, you probably will get away with it if you weigh it, stamp it as a letter, and drop it in a post box. It just isn't what the rate-makers intended.