Preheat the oven to 400F degrees and spray an 11x7-inch baking dish (or similar size casserole dish) with nonstick spray; set aside.
Combine the corn, sour cream, melted butter, eggs, cheese, Jiffy mix, chives, mustard powder, and 2 of the chopped hotdogs in a large bowl.
Pour into the prepared baking dish and top with the remaining chopped hotdog.
Bake for 20 to 25 minutes until the center only slightly jiggles (oven times vary depending on the type of baking dish you used)
Allow to cool for a few minutes then garnish with additional chives and serve.
Notes
PLEASE NOTE: Oven times vary but the edges should be lightly browned. Some people have said it has taken longer in their ovens. It all depends if your oven is heating to the correct temperature (sometimes and oven will say 400F but its not correctly heating to that temperature which can happen over time to many ovens - it's always good to invest in a n oven thermometer), what oven rack you have it on, etc. So please don't only go by time, make sure it is set before removing from your oven.
The mustard powder does not create an overpowering mustard flavor at all.