Thanks - I was hesitant to name the restaurant because I'm not 100% certain what happened but since people asked it was the outdoor Cantina at Mexico. Specifically the nachos. We live in the Orlando area and have shared the nachos previously without incident.
I will contact guest services and see if I get any response from then before going to the restaurant directly...3 of the 4 people who shared the nachos were hit with vomiting which seems suspicious to me. The 4th person (my DH) didn't feel well but he's a guy who could eat 2 week old spoiled milk and not be bothered.
Worst case, I'll speak to the restaurant directly when I'm back at WDW in 2 weeks.
I also wanted to add that we eat at WDW a lot and this is the 1st time that anything like this has happened. We've also eaten this specific dish several times w/out incident. I believe on the whole Disney takes food safety very seriously and this was just a fluke thing. I just emailed guest services to let them know.