How damaging are salted mixed nuts, with beer?!

Well, I'm not sure what American beer is like compared to my native English stuff but I'll give a go at answering anyway!
Nuts are a good source of fibre and a few varieties have many added benefits, peanuts can lower the risk of clogged up arteries, and can help prevent spina bifida in a newly conceived foetus (bet you didn't know that!) Cashews are filled with iron, and by ratio are much better for you than Spinach in terms of the amount of iron, so nuts are very healthy, salted nuts aren't perhaps as healthy but even so it's marginally different.
In answer to your question, beer is quite fattening in itself, as it contains tons of calories but seeing as this is only for one day and it sounds like you'll have a right laugh it won't be a problem as long as you don't make a habit of drinking beer in excess and loads of nuts every day!
Hope this helps!

ME!

Lots of salt in a whole pounds, but you'll probably wash it all out with the beer