Nation Wars, events.
I mean, is there a way to farm them?
There's no other way, but there will be one soon.
How does nation war works in terms of getting supply tokens?
You get them mailed to you by the system based on the amount of points you've made during NW (+ placement of your nation as in 1st, 2nd, 3rd or 4th).
Sorry let me change my question. How does the point rewards work?
You obtain points based on just about anything you do, though some things give more points than others. Grabbing the flag, capping the flag, killing, buffing, etc. all gives you your own personal credits.
Can you lose credits?and How do you check how many credits you have?