Well...
The problem with drinking a lot of alcohol and then consuming MDMA (or any amphetamine) is that you're going to have an increased danger of dehydration, due to the effects of the alcohol. So be aware that if you're going to mix the two, you need to drink a bit more water than you would usually when you're out.
Secondly, the combination of Alcohol & MDMA will increase the intensity of your peak, and in moderation you will feel substantially more euphoric effects, though some of the feeling of 'clarity' may be decreased. According to some research which I saw on bluelight, but which I can't actually remember the name of the study. A few beers while peaking increases the blood plasma concentration of MDMA by 13%, which basically equates to peaking harder. You should be aware also though, that you're going to be doing your liver double damage simply because its taking hits from the alcohol and from the MDMA so go easy and don't go overboard at all. It will do you more damage.
As to whether it will make you more prone to nausea, yes, it possibly will, especially if its beer, because its going to play with the PH balance of your stomach, and there's going to be a LOT of fluid sloshing around in there. But if you stay relatively moderate with your beer intake and MDMA intake there's no reason you shouldn't have a spankingly good time.
-plaz out-