Thought it was quite clever, especially the add-on at the end. The following are points I think might've influenced their decision.
*the video quality/lighting/fx was looking a bit budget. I didn't really mind that but hey, they might.
*Although you showed a funny scenario, you didn't really put emphasis on the chips itself. In other words: I laughed but it didn't make me want to taste the doritos as the commercial didn't make them very desirable.
*With an overused musical theme and a very bland start the commercial doesn't really do anything for you until 00:14 seconds in. That's long for a commercial! That's 14 seconds for people to switch channels. Try to grab the attention from the first shot and pace up the editing.
Hope this helps a bit, good effort nonetheless :)