Hi! I'm a history student ambassador at Lancaster University and thought I might be able to help you here.
Lancaster is definitely not a party town, although there is enough nightlife for people to take part in if they want to. It's a pretty small town but it is 100% possible to get a part time job - I had one in my third year (this year) and know plenty of people that had them all three years. There are on-campus jobs, which are pretty high in-demand, and jobs in the town which is only a short bus-ride away and accessible by bus throughout the night if your job runs late (it is also a very safe city from my experience). Lancaster also has a very large international student-community, and has previously won the international university of the year award.
While I can't say anything about Nottingham, I would definitely recommend Lancaster.
Hope this helps, please reach out if you have any more questions.
~ Georgia