I'm guessing you meant "sweater," not seater.
I seldom find black pants to be a good choice, but assuming you like black pants, black's an easy color to match. So I guess a blue sweater would go with it okay.
I'd probably want to keep the blue from going too dark, though. Since really dark blue is just too similar to black (particularly so under various types of artificial light), and that tends to be a not so great look.
But, as with nearly all "Does it look nice..." questions, there's no substitute for actually seeing a picture of you in the pants and sweater in question.