Node.js is the perfect language for a Twitter bot - any bot actually. I've written one myself. Currently still testing it, running 93 bots on an old Celeron Linux PC without any noticeable lag or issues. It's not even causing any noticeable load at all - except for debugging pupose. I would guess 1000 concurrent bots shouldn't be any issue either.
What I can recommend, from my experience are two things, start with a web server. I used command line tools and log files, which is haunting me now because it became very complex to keep an eye on everything and adding an express server now is a lot of work. And I can recommend to use a heartbeat function in the center of the code. This allows for pretty much an unlimited amount of bots even on a small virtual server account.