What other tests have you had done prior to your visit with the surgeon?
I question whether or not a Nissen would help you. Have you had a stomach emptying test?
I do know before I had surgery, I would get severe reflux episodes where I had a lump feeling at the LES level, and could eat little or nothing. I never burped or regurged, though. I just didn't eat.
Have you discussed the fact that you force regurgitation of food an burps? I don't see how that would be good for you. Has your GI doc told you that he/she thinks surgery would help your condition?
You need to have a highly qualified, experienced (having done hundreds or a thousand+ procedures) surgeon to help you make that decision. If you're not the right candidate for surgery, it will only make your problems worse.
If the surgery solved your problem, you wouldn't need to burp or regurg. The problem might come if it has become habitual, and you can't stop yourself post surgery.
I think your situation requires some excellent evaluation and consideration.
Good luck with making your decision and finding help for your problem!