Hi Sandy and Starry. Welcome to the forum.
I had a giant paraesophageal hiatal hernia (GPEH) due to a car accident. My seatbelt pushed my stomach up into my chest where it got stuck. That was a couple of years ago, so I've been through what you can expect to get. It's not fun, but it's lifesaving surgery, critical to get done ASAP.
I posted tons on the forum as I jumped through the hoops, went through the surgery, recovered. I'm a senior, so it you are younger you will do better. Don't get too hysterical when you read my posts. But it's a lot longer surgery (mine was 4 1/2 hours) because of having to take down the stomach so much, and it's right next to the heart, separated only by a thin membrane.
My surgery was done in a large university setting, and I would not go to anything less. It doesn't matter if the surgeon has done lots of trgular ops, just if he's done a bunch of GPEH surgeries and has a good team. I had a Toupet procedure because I have a very weak swallow due to having polio as a kid. You might be able to tolerate a regular Nissen, but make sure not to skip the testing!
To read the info already posted, please put various keywords in the search box at the top of the page. paraesophageal hernia, GPEH, stomach in chest ... You can also look up just my posts by clicking on my name, then go to the older posts for the stories. I've posted links to some informative websites too.