How much chocolate does it take to kill a dog?

For what ever reason our dog likes to steal chocolate. Last week my fianc� put the gate up in the bedroom door way to keep the dog in the room while he came to get me from work to eat lunch. We get in the door and she's out of the room and we found that she had eaten almost an entire bag of Fritos honey BBQ chips plus about 15 hersheys nugget candies. We normally don't leave her in the house while we are gone but he didn't expect her to push her way under the gate. Then tonight we left the room for a minute, came back and found that she had eaten at least half a thing of chips-a-hoy chocolate chip cookies. So we are wondering how much more of this can she do before killing herself? She's a couple months under two years old and her previous owners didn't teach her very much. We do know that after eating the candies, her poop looked like a pile of chocolate. I was always told that chocolate will give dogs worms but how do we show her that it's not her food. I mean she even ate the wrappers on those candies!! The weird thing is we had a box of crackers out for the longest time and she never went after those. Also the first time he tried to leave her inside she stole a few Oreos. Yes we now know we are NOT trusting her alone when we have food.