Welcome to Healing Well! It sounds like you've got a lot going on, and with reflux that severe, it's a good thing you're going forward with the surgery.
I haven't suffered with the same issues as you, but did have GERD related lung problems. I have asthma anyway, and my reflux caused it to be uncontrollable. My lungs were horrible, and I was on high doses of steroids to keep breathing.
I had the Nissen fundoplication surgery in February 2009, and it definitely made a big difference. My lungs took a couple of months to heal, and are now far better than they had been for years.
It sounds like your reflux is really severe--much worse than mine was. I'm sure that the reflux isn't helping your lung condition.
I'm sure it's tricky with chemo, but it sounds like it would be good to move forward quickly. Do you have a surgeon chosen? If you've read many posts on this site, you'll hear over and over about the importance of choosing a surgeon who has don many Nissens and has a good track record. Your surgeon should have done at least hundreds of Nissen surgeries. It's a tricky procedure and experience makes a big difference to ensure a successful outcome.
Again, I'm glad you've joined us! I'm sure others will be by soon to share their own experiences with you.